Ccache 4.6.3

Release date: 2022-08-27

Bug fixes

  • Fixed MSVC support (regression in ccache 4.6.2).
    [contributed by Joel Rosdahl]

  • Fixed detection of PCH header for concatenated -include option (e.g., -includepch.h instead of -include pch.h).
    [contributed by Joel Rosdahl]

Build improvements

  • Fixed build with musl when using GCC 12.
    [contributed by Khem Raj]

Test improvements

  • Disabled the "Failure to write output file" when running on a filesystem that doesn’t support read-only directories.
    [contributed by Joel Rosdahl]

Ccache 4.6.2

Release date: 2022-08-22

Bug fixes

  • Fixed a race condition that could lead to a crash if a file in the cache is removed with unlucky timing, e.g. by another ccache process doing cache cleanup.
    [contributed by Joel Rosdahl]

  • Dependency file rewriting will now always be performed if base_dir/CCACHE_BASEDIR is active. This fixes a problem with the dependency file content when Clang is used with -fsanitize=address.
    [contributed by Joel Rosdahl]

  • Fixed handling of error condition for --hash-file/--checksum-file.
    [contributed by Joel Rosdahl]

  • Made sure to enable the inode cache only if subsecond stat timestamps are available.
    [contributed by Joel Rosdahl]

  • Added a work-around for a Clang bug when writing to a full NFS file system.
    [contributed by Joel Rosdahl]

  • Made failure writing to the output file increment the “bad output file” counter instead of “cache miss”.
    [contributed by Joel Rosdahl]

  • Fixed false positive cache hits for code constructions similar to asm(".incbin" " \"file\"").
    [contributed by Joel Rosdahl]

  • Fixed false success for -fcolor-diagnostics probe with GCC. A side effect of this is that a compiler type that ccache can’t identify from the compiler name (such as /usr/bin/cc where cc is not a symlink) from now on won’t produce color diagnostics when used via ccache even if the compiler actually is GCC or Clang.
    [contributed by Joel Rosdahl]

  • More cases of invalid secondary storage URLs are now handled gracefully.
    [contributed by Joel Rosdahl]

  • Fixed the display of maximum cache size in ccache -s if it’s 0 (= unlimited).
    [contributed by Joel Rosdahl]

  • Removed AsciiDoc markup from help text of --trim-dir.
    [contributed by Joel Rosdahl]

  • The temporary directory is now cleaned up properly even if it’s left unconfigured.
    [contributed by Joel Rosdahl]

  • Made cleanup of the temporary directory not rely a directory timestamp.
    [contributed by Joel Rosdahl]

  • Made sure to retain mtime/atime when recompressing cache files with -X/--recompress.
    [contributed by Joel Rosdahl]

  • The correct umask is now used when populating the primary cache from a secondary cache.
    [contributed by Joel Rosdahl]

  • Fixed creation of temporary files on file systems that don’t support hard links (such as FAT32).
    [contributed by Joel Rosdahl]

  • Added knowledge about -Wa,…​=file so that ccache then falls back to running the real compiler.
    [contributed by Joel Rosdahl]

  • Corrected handling of space in paths when using response file on Windows.
    [contributed by Sergey Semushin]

  • Fixed crash due to empty include filename in preprocessor output generated by f2c.
    [contributed by Oleg Sidorkin]

Build improvements

  • Fixed build problems with a development version of GCC 13.
    [contributed by Joel Rosdahl]

  • Fixed build problems with MSVC.
    [contributed by Florin Trofin]

Test improvements

  • Clang warnings from the “-fdebug-prefix-map” test are now suppressed.
    [contributed by Joel Rosdahl]

  • Made sure to only run the “-ftest-coverage + -fprofile-dir” test with GCC.
    [contributed by Joel Rosdahl]

  • Fixed printing of error messages with embedded newlines.
    [contributed by Joel Rosdahl]

  • Fixed warning when running the “inode_cache” test in isolation.
    [contributed by Joel Rosdahl]

  • Fixed test failure when the compiler used for testing is an old ccache version masquerading as the compiler.
    [contributed by Joel Rosdahl]

Documentation improvements

  • Mentioned that mtime is used for LRU cleanup.
    [contributed by Joel Rosdahl]

Ccache 4.6.1

Release date: 2022-05-15

New features

  • Added support for passing a directory to the MSVC /Fo option.
    [contributed by Orgad Shaneh]

  • Added knowledge about the -imsvc compiler option.
    [contributed by Jacob Young]

  • Added knowledge about the -z linker option.
    [contributed by Joel Rosdahl]

Bug fixes

  • Improved handling of .gcno files in combination with absolute input file paths.
    [contributed by Joel Rosdahl]

  • Adapted to changes in GCC 9+ .gcno files, which contain the current working directory, by including said directory in the hash. You can opt out of this by enabling “gcno_cwd sloppiness”.
    [contributed by Joel Rosdahl]

  • A preexisting object file is no longer considered when using -fsyntax-only.
    [contributed by Joel Rosdahl]

  • Authenticate with Redis before database selection.
    [contributed by an anonymous user]

  • Don’t exit with an error on failure reading a cached file.
    [contributed by an anonymous user]

  • Bail out on too hard MSVC environment variables CL and _CL_.
    [contributed by Joel Rosdahl]

  • Only use /run/user/<UID>/ccache-tmp as the temporary directory if it’s writable.
    [contributed by Joel Rosdahl]

  • Fixed handling of the final newline in cached standard output from the compiler.
    [contributed by Orgad Shaneh]

  • Fixed a bug related to distcc markers in standard error output.
    [contributed by Joel Rosdahl]

  • Paths to base_dir are now properly normalized on Windows.
    [contributed by Vili Väinölä and Joel Rosdahl]

  • Fixed handling of MSVC /Fp and /Yu options with concatenated path.
    [contributed by Joel Rosdahl]

  • Fixed “Multiple precompiled headers used” error if MSVC /Yu option is used after /Fp.
    [contributed by Alexey Telishev]

  • Check for short reads when reading strings in result/manifest files.
    < [contributed by Gregor Jasny]

  • Log expanded secondary storage URL in put/remove.
    [contributed by Joel Rosdahl]

  • Fixed logging of statistics counters with value higher than one in debug log and stats log.
    [contributed by Joel Rosdahl]

  • Avoid incorrect error log message for Redis write operations in reshare mode.
    [contributed by Joel Rosdahl]

  • Support Redis URL without host (meaning localhost).
    [contributed by Joel Rosdahl]

Build improvements

  • Prefer CMake find module for hiredis and zstd packages.
    [contributed by Cristian Adam and Joel Rosdahl]

  • Fixed building and linking BLAKE3 with MSVC.
    [contributed by Rafael Kitover]

  • Fixed static linkage with hiredis on Windows.
    [contributed by Orgad Shaneh]

  • Fixed miscompile of nonstd::expected on MSVC v19.22.
    [contributed by Jacob Young]

  • Fixed build arguments to clang-cl.
    [contributed by Jacob Young]

  • Fixed parsing of MSVC response files.
    [contributed by Jacob Young]

  • Support Git 1.x when determining ccache version.
    [contributed by Joel Rosdahl]

Test improvements

  • Worked around an endianness problem which affected builds and tests on big-endian systems.
    [contributed by Joel Rosdahl]

  • A C++-capable compiler is no longer required for the test suite.
    [contributed by Joel Rosdahl]

  • Fixed an issue with inode cache tests, leading to sporadic failures in the inode test suite when running many parallel tests.
    [contributed by Joel Rosdahl]

  • Fixed sporadic failures in the profiling test suite.
    [contributed by Jacob Young]

Documentation improvements

  • Added reference to example build configs in installation instructions.
    [contributed by an anonymous user]

  • Default cache locations are now mentioned for Windows and macOS as well.
    [contributed by Joel Rosdahl]

  • Added a warning about usage of base_dir.
    [contributed by Joel Rosdahl]

Ccache 4.6

Release date: 2022-02-27

New features

  • Added support for caching calls to Microsoft Visual C++ (MSVC) and clang-cl (MSVC compatibility for Clang).
    [contributed by Cristian Adam, Luboš Luňák, Orgad Shaneh and Joel Rosdahl]

  • Added an option to use a bearer token with the HTTP backend. This makes it possible to use e.g. Google Cloud Storage as a secondary storage backend.
    [contributed by an anonymous user]

  • Added support for caching standard output from the compiler.
    [contributed by Luboš Luňák and Joel Rosdahl]

  • Added a new --inspect option for debugging cache entries, replacing the previous --dump-manifest and --dump-result options.
    [contributed by Joel Rosdahl]

  • Enabled HTTP keep-alive by default.
    [contributed by Joel Rosdahl]

Bug fixes

  • Fixed copying of binary files on Windows.
    [contributed by R. Voggenauer]

  • Improved detection of the .incbin assembler directive to reduce false positives.
    [contributed by Alexey Sheplyakov]

  • Ccache now verifies that /run/user/<UID>/ccache-tmp is writable before using it for temporary files.
    [contributed by Joel Rosdahl]

  • Fixed statistics output for secondary storage.
    [contributed by Orgad Shaneh]

  • Fixed a problem when copying a cache entry from secondary storage into an empty primary storage.
    [contributed by Joel Rosdahl]

  • Visual Studio .rsp files with UTF-16LE encoding are now handled correctly.
    [contributed by Vili Väinölä]

  • Made conversion to relative paths more reliable on Windows.
    [contributed by Marius Zwicker]

  • The process umask is now respected when making hard linked files read only.
    [contributed by Joel Rosdahl]

  • A forced recache is no longer considered a “direct cache miss”.
    [contributed by Joel Rosdahl]

Documentation improvements

  • Corrected reference to the debug_dir option.
    [contributed by Joel Rosdahl]

  • Improved documentation of --config-path.
    [contributed by Joel Rosdahl]

  • Added documentation that compiler plugins are hashed too.
    [contributed by Philipp Gortan]

Test improvements

  • The “trim_dir” test suite is now only run when cleanup tests are enabled.
    [contributed by Joel Rosdahl]

Ccache 4.5.1

Release date: 2021-11-17

Bug fixes

  • Fixed entry_size field for result entries. This bug affected the recompression feature (-X/--recompress) in ccache 4.5.
    [contributed by Joel Rosdahl]

  • The actual compression level is now once again stored in the cache entry header.
    [contributed by Joel Rosdahl]

  • Corrected error handling for non-constructible secondary storage backends. For instance, this avoids a crash when a Redis server can’t be reached.
    [contributed by Joel Rosdahl]

Ccache 4.5

Release date: 2021-11-13

New features

  • Made various improvements to the cache entry format. Among other things, the header now contains a creation timestamp and a note of the ccache version used to create the entry. The cache entry checksum has also been upgraded to use 128-bit XXH3 instead 64-bit XXH3.
    [contributed by Joel Rosdahl]

  • Added support for cache namespaces. If a namespace configured, e.g. using CCACHE_NAMESPACE=some_string, the namespace string will be added to the hashed data for each compilation. This will make the associated cache entries logically separate from cache entries in other namespaces, but they will still share the same storage space. Cache entries can also be selectively removed from the primary cache with the new command line option --evict-namespace, potentially in combination with --evict-older-than.
    [contributed by Joel Rosdahl]

  • Made HTTP keep-alive configurable, defaulting to off for now.
    [contributed by Gregor Jasny]

  • Added support for rewriting absolute path to Clang option --gcc-toolchain.
    [contributed by Joel Rosdahl]

Compatibility notes

  • A consequence of the changed cache entry format is that ccache 4.5 will not share cache entries with earlier versions. Different ccache versions can however still use the same cache storage without any issues.

Bug fixes

  • Fixed a problem with special characters in the user info part of URLs for HTTP storage.
    [contributed by Russell McClellan]

  • Fixed win32 log messages about file locks.
    [contributed by Luboš Luňák]

  • Fixed debug directory handling on Windows.
    [contributed by Luboš Luňák]

  • The hard link and file clone features are now disabled when secondary storage is used since they only work for the local primary cache.
    [contributed by Joel Rosdahl]

Ccache 4.4.2

Release date: 2021-09-28

Bug fixes

  • Fixed a bug introduced in 4.4 where ccache could produce false direct cache hits in some situations if it decides to disable the direct mode temporarily (e.g. due to “too new header” file).
    [contributed by Joel Rosdahl]

Test improvements

  • Use shell builtin pwd command for basedir test.
    [contributed by Kira Bruneau]

  • Cope with CC being a wrapper script that uses ccache.
    [contributed by Joel Rosdahl]

Ccache 4.4.1

Release date: 2021-09-11

New features

  • The secondary storage statistics section of -s/--show-stats is now shown only if it’s non-empty or with two verbose options.
    [contributed by Joel Rosdahl]

  • Added display of statistics counters for misses. Previously they were only implicit in the “hits + misses” sums.
    [contributed by Joel Rosdahl]

Bug fixes

  • Fixed spurious crashes when using the HTTP or Redis backend and the remote connection hung up.
    [contributed by Joel Rosdahl]

  • Made sure to always store configuration origin value.
    [contributed by Gregor Jasny]

Build improvements

  • The matching version of lld is now used for Clang.
    [contributed by Gregor Jasny]

  • The standard linker is now used if IPO (LTO) is enabled.
    [contributed by Gregor Jasny]

  • Disabled IPO (LTO) for MinGW toolchains since they seem to be generally broken.
    [contributed by Gregor Jasny]

  • Fixed build errors with Clang on Windows.
    [contributed by Orgad Shaneh]

Test improvements

  • Fixed .incbin test with newer binutil versions.
    [contributed by Joel Rosdahl]

  • Fixed basedir test suite failure when using a symlinked CWD.
    [contributed by Joel Rosdahl]

  • Improved output of differing text files on failure.
    [contributed by Joel Rosdahl]

Ccache 4.4

Release date: 2021-08-19

New features

  • Made it possible to share a cache over network or on a local filesystem. The configuration option secondary_storage/CCACHE_SECONDARY_STORAGE specifies one or several storage backends to query after the primary local cache storage. It is also possible to configure sharding (partitioning) of the cache to spread it over a server cluster using Rendezvous hashing. See the Secondary storage backends chapter in the manual for details.
    [contributed by Joel Rosdahl]

  • Added an HTTP backend for secondary storage on any HTTP server that supports GET/PUT/DELETE methods. See How to set up HTTP storage for hints on how to set up an HTTP server for use with ccache.
    [contributed by Gregor Jasny]

  • Added a Redis backend for secondary storage on any server that supports the Redis protocol. See How to set up Redis storage for hints on how to set up a Redis server for use with ccache.
    [contributed by Anders F Björklund]

  • Added a filesystem backend for secondary storage. It can for instance be used for a shared cache over networked filesystems such as NFS, or for mounting a secondary read-only cache layer into a build container.
    [contributed by Joel Rosdahl]

  • Added --trim-dir, --trim-max-size and --trim-method options that can be used to trim a secondary storage directory to a certain size, e.g. via cron.
    [contributed by Joel Rosdahl]

  • Added a configuration option reshare/CCACHE_RESHARE which makes ccache send results to secondary storage even for primary storage cache hits.
    [contributed by Joel Rosdahl]

  • Added new statistics counters for direct/preprocessed cache misses, primary storage hits/misses, secondary storage hits/misses/errors/timeouts and forced recaches.
    [contributed by Joel Rosdahl]

  • Improved statistics summary. The -s/--show-stats option now prints a more condensed overview where the counters representing “uncacheable calls” are summed as uncacheable and errors counters. The summary shows hit rate for direct/preprocessed hits/misses, as well as primary/secondary storage hits/misses. More details are shown with -v/--verbose. Note: Scripts should use --print-stats (available since ccache 3.7) instead of trying to parse the output of --show-stats.
    [contributed by Joel Rosdahl]

  • Added a “stats log” feature (configuration option stats_log/CCACHE_STATSLOG), which tells ccache to store statistics in a separate log file specified by the user. It can for instance be used to collect statistics for a single build without interference from other concurrent builds. Statistics from the log file can then be viewed with ccache --show-log-stats.
    [contributed by Anders F Björklund]

  • Added support for clang’s --config option.
    [contributed by Tom Stellard]

  • Added support for one -Xarch_* option that matches a corresponding -arch option.
    [contributed by Joel Rosdahl]

  • Renamed the --directory option to --dir for consistency with other options.
    [contributed by Joel Rosdahl]

  • Made the --config-path and --dir options affect the whole command line so that they don’t have to be put before -s/--show-stats.
    [contributed by Joel Rosdahl]

  • Made --dump-manifest and --dump-result accept filename - for reading from standard input.
    [contributed by Anders F Björklund]

  • Made the output of --print-stats sorted.
    [contributed by Joel Rosdahl]

  • Added more internal trace points.
    [contributed by Joel Rosdahl]

Bug fixes

  • Fixed a crash if using base_dir and $PWD is set to a relative path.
    [contributed by Joel Rosdahl]

  • Fixed a bug with -fprofile-generate where ccache could give false positive cache hits when compiling with relative paths in another directory.
    [contributed by Joel Rosdahl]

  • Fixed a bug in debug_dir/CCACHE_DEBUGDIR. The absolute path to the object file was not created correctly if the object file didn’t already exist.
    [contributed by Joel Rosdahl]

  • Disabled preprocessor hits for pre-compiled headers with Clang again.
    [contributed by Arne Hasselbring]

  • Fixed a problem when using the Gold linker on MIPS by only probing for a faster linker in dev build mode and on x86_64.
    [contributed by Joel Rosdahl]

  • Made the -DENABLE_TRACING=1 mode work again.
    [contributed by Anders F Björklund]

Changed tooling

  • A C++14 compiler or newer is now required to build ccache. For GCC, this means version 6 or newer in practice.

  • CMake 3.10 or newer is now required to build ccache.

  • Asciidoctor is now required to build ccache documentation.

Build/test/documentation improvements

  • Fixed an issue in the modules test suite that showed up when running the ccache test suite with the clang wrapper provided by Nixpkgs.
    [contributed by Ryan Burns]

  • Made the nvcc_ldir test suite require a working NVCC.
    [contributed by Michael Kruse]

  • Made the ivfsoverlay test suite more robust.
    [contributed by Michael Kruse]

  • Fixed issue with usage of /FI when building ccache with MSVC.
    [contributed by Michael Kruse]

  • Fixed Apple Clang detection in the integration test suite.
    [contributed by Gregor Jasny]

  • Made clang the default compiler when running the test suite on macOS.
    [contributed by Gregor Jasny]

  • Silenced stray printout from "-P -c" test case.
    [contributed by Joel Rosdahl]

  • Fixed selection of the ccache binary to use when running the test suite with multi-config generators like Xcode.
    [contributed by Gregor Jasny]

  • Fixed CMake feature detection for ctim/mtim fields in struct stat.
    [contributed by Gregor Jasny]

  • Fixed issue with not linking to .lib correctly on Windows.
    [contributed by R. Voggenauer]

  • Made it possible to override CCACHE_DEV_MODE on the command line.
    [contributed by Joel Rosdahl]

  • Improved HTML documentation style.
    [contributed by Joel Rosdahl with minor fixes by Orgad Shaneh]

Ccache 4.3

Release date: 2021-05-09

New features

  • Ccache now ignores the Clang compiler option -ivfsoverlay and its argument if you opt in to “ivfsoverlay sloppiness”. This is useful if you use Xcode, which uses a virtual file system (VFS) for things like combining Objective-C and Swift code.

  • When using -P in combination with -E, ccache now reports this as “called for preprocessing” instead of “unsupported compiler option”.

  • Added support for -specs file.specs and --specs file.specs without an equal sign between the arguments.

Bug fixes

  • “Split dwarf” code paths are now disabled when outputting to /dev/null. This avoids an attempt to delete /dev/null.dwo.

  • Made the stat/lstat wrapper function for Windows treat pending deletes as missing files.

  • Fixed a bug that made ccache process header files redundantly for some relative headers when using Clang.

  • The object path is now included in the input hash when using -fprofile-arcs (or --coverage) since the object file embeds a .gcda path based on the object file path.

Build improvements

  • Added an ENABLE_DOCUMENTATION build option (default: true) that can be used to disable the build of documentation.

  • Fixed detection of pthread features.

  • Quote CMake variables expansions to avoid errors when ${CMAKE_C_FLAGS_RELWITHDEBINFO} or ${CMAKE_CXX_FLAGS_RELWITHDEBINFO} expands to the empty string.

Ccache 4.2.1

Release date: 2021-03-27

Bug fixes

  • Ccache now only duplicates the stderr file descriptor into $UNCACHED_ERR_FD for calls to the preprocessor/compiler. This works around a complex bug in interaction with GNU Make, LTO linking and the Linux PTY driver.

  • Fixed detection of color diagnostics usage when using -Xclang -fcolor-diagnostics options.

  • The -frecord-gcc-switches compiler option is now handled correctly to avoid false positive cache hits.

  • Made it possible for per-compilation debug log files to be written in most argument processing error scenarios. Previously, ccache would only write debug log files if the argument processing phase was successful.

  • Made ccache bail out on too hard Clang option -gen-cdb-fragment-path.

  • The run_second_cpp made is now enforced on macOS if -g is used since newer Clang versions on macOS produce different debug information when compiling preprocessed code.

  • Made ccache only reject -f(no-)color-diagnostics for a known GCC compiler. This fixes a problem when using said option with Clang on macOS.

  • Implemented a better stat/lstat wrapper function for Windows.

  • Fixed a bug where ccache could return stale cache results on Windows.

  • Fixed handling of long command lines on Windows.

Portability and build improvements

  • Build configuration scripts now probe for atomic increment as well. This fixes a linking error on Sparc.

  • An existing CMake log message level is now used when warning about not finding asciidoc.

  • Added support for building ccache with xlclang++ on AIX 7.2.

  • Fixed assertion in the “Debug option” test.

  • Made build configuration skip using ccache when building with MSVC.

  • Upgraded to doctest 2.4.6. This fixes a build error with glibc >= 2.34.


  • Fixed markup of compiler_type value other.

  • Fixed markup of debug_dir documentation.

  • Fixed references to the extra_files_to_hash configuration option.

Ccache 4.2

Release date: 2021-02-02

New features

  • Improved calculation of relative paths when using base_dir to also consider canonical paths (i.e. paths with dereferenced symlinks) as candidates.

  • Added a debug_dir (CCACHE_DEBUGDIR) configuration setting for specifying a directory for files written in debug mode.

  • Added support for compiler option -x cuda, understood by Clang.

  • The value of the SOURCE_DATE_EPOCH variable is now only hashed if it potentially affects the output from ccache. This means that ccache now (like before version 4.0) will be able to produce cache hits for source code that doesn’t contain DATE or TIME macros regardless of the value of SOURCE_DATE_EPOCH.

Bug fixes

  • Fixed a bug where a non-Clang compiler would silently accept the Clang-specific -f(no-)color-diagnostics option when run via ccache. This confused feature detection made by e.g. CMake.

  • Improved creation of temporary files on Windows. Previously, ccache would in practice reuse temporary filenames on said platform resulting in various problems with parallel builds.

  • Fixed creation of parent directories when creating a lock file on Windows.

  • Fixed a race condition related to removal of temporary files.

  • Improved calculation of directory name for a Windows-style path.

  • A compilation result is now not stored in the cache if an included preprocessed header file is too new. This fixes a bug where the content of a newly created preprocessed header file could be missing from the hash, resulting in a false positive cache hit.

  • Fixed calculation of the split DWARF filename for an object filename with zero or multiple dots.

  • Fixed retrieval of the object file the destination is /dev/null.

Portability and build improvements

  • Additional compiler flags like -Wextra -Werror are now only added when building ccache in developer mode.

  • The developer build mode no longer enables -Weverything for Clang.

  • _XOPEN_SOURCE is now defined appropriately on FreeBSD to fix missing declaration of isascii.

  • Improved detection of buildability of BLAKE3 assembler files.

  • Disabled build of inode cache code on OSes without pthread_mutexattr_setpshared, such as OpenBSD.

  • Made static linking the default for a Windows MinGW build.

  • Removed legacy fallback replacements of mkstemp and realpath.

  • Improved detection of SSE/AVX support.

  • Improved detection of support for the AVX2 target attribute.

  • Configuration scripts now try to detect and enable BLAKE3’s Neon support.

  • Made it possible to run the integration test suite on macOS.

  • Fixed building of 32-bit unit tests on macOS.

  • Made it possible to compile ccache for C++17.

  • Fixed printing of 64-bit time_t on 32-bit architectures like RISCV32.

  • Made sure to only use ASCII characters in the manual’s AsciiDoc source code to make it possible to generate documentation in non-UTF8 locales.

  • Upgraded to optional-lite 3.4.0, fmt 7.1.3, doctest 2.4.4 and zstd 1.4.8.

  • Took steps towards being able to run the test suite on Windows.


  • Improved wording of compiler_check string values.

  • Improved documentation of compression levels and the -X/--recompress option.

  • Improved consistency of terms in the manual.

  • HTML documentation is now built and installed by default if possible.

  • Fixed incorrect documentation of configuration option cache_dir.

  • Added hint on how to link statically with libzstd.

  • Mention that ccache requires the -c compiler option.

Ccache 4.1

Release date: 2020-11-22

New features

  • Symlinks are now followed when guessing the compiler. This makes ccache able to guess compiler type “GCC” for a common symlink chain like this: /usr/bin/cc/etc/alternatives/cc/usr/bin/gccgcc-9x86_64-linux-gnu-gcc-9.

  • Added a new compiler_type (CCACHE_COMPILERTYPE) configuration option that allows for overriding the guessed compiler type.

  • Added support for caching compilations with -fsyntax-only.

  • Added a command line option --config-path, which specifies the configuration file to operate on. It can be used instead of setting CCACHE_CONFIGPATH temporarily.

Bug fixes

  • The original color diagnostics options are now retained when forcing colored output. This fixes a bug where feature detection of the -fcolor-diagnostics option would succeed when run via ccache even though the actual compiler doesn’t support it (e.g. GCC <4.9).

  • Fixed a bug related to umask when using the umask (CCACHE_UMASK) configuration option.

  • Allow ccache ccache compiler …​ (repeated ccache) again.

  • Fixed parsing of dependency file in the “depend mode” so that filenames with space or other special characters are handled correctly.

  • Fixed rewriting of the dependency file content when the object filename includes space or other special characters.

  • Fixed runtime detection of AVX2 support, not relying on the sometimes broken __builtin_cpu_support routine.

  • Added missing parameters to a log call, thus avoiding a crash when it is found out at runtime that file cloning is unsupported by the OS.

Portability and build fixes

  • The ccache binary is now linked with libatomic if needed. This fixes build problems with GCC on ARM and PowerPC.

  • Fixed build of BLAKE3 code with Clang 3.4 and 3.5.

  • Fixed “use of undeclared identifier 'CLONE_NOOWNERCOPY'” build error on macOS 10.12.

  • Fixed build problems related to missing AVX2 and AVX512 support on older macOS versions.

  • Fixed static linkage with libgcc and libstdc++ for MinGW and made it optional.

  • Fixed conditional compilation of “robust mutex” code for the inode cache routines.

  • Fixed badly named man page filename (Ccache.1 instead of ccache.1).

  • Disabled some tests on ancient Clang versions.

Other improvements and fixes

  • The man page is now built by default if the required tools are available.

  • Use CMake A2X_EXE variable instead of hardcoded a2x.

  • Improved build errors when building ccache with very old compiler versions.

  • Fall back to version “unknown” when Git is not installed.

  • Documented the relationship between CCACHE_DIR and -d/--directory.

  • Fixed incorrect reference and bad markup in the manual.

Ccache 4.0

Release date: 2020-10-18

Summary of major changes

  • Changed the default cache directory location to follow the XDG base directory specification.

  • Changed compression algorithm from Deflate (zlib) to Zstandard, enabled by default.

  • Added functionality for recompressing cache content with a higher compression level.

  • Changed hash algorithm from MD4 to BLAKE3.

  • Added checksumming with XXH3 to detect data corruption.

  • Improved cache directory structure.

  • Added support for using file cloning (AKA “reflinks”).

  • Added an experimental “inode cache” for file hashes.

Compatibility notes

  • The default location of the cache directory has changed to follow the XDG base directory specification (more details below). This means that scripts can no longer assume that the cache directory is ~/.ccache by default. The CCACHE_DIR environment variable still overrides the default location just like before.

  • The cache directory structure has changed compared to previous versions (more details below). This means that ccache 4.0 will not share cache results with earlier versions. It is however safe to run ccache 4.0 and earlier versions against the same cache directory: cache bookkeeping, statistics and cleanup are backward compatible, with the minor exception that some statistics counters incremented by ccache 4.0 won’t be visible when running ccache -s with an older version.

Changed tooling

  • CMake is now used instead of Autoconf for configuration and building.

  • A C++11 compiler, a C99 compiler and CMake 3.4.3 or newer are now required to build ccache.

  • Ccache can now be built using Microsoft Visual C++.

Detailed functional changes

  • All data of a cached result is now stored in a single file called “result” instead of up to seven files. This reduces inode usage and improves data locality.

  • Added compression of result and manifest files using the Zstandard algorithm. Compression is enabled by default with compression level 1. This makes ccache able to store more data in the cache. Previously compression using Deflate (zlib) was available but disabled by default. Files can be recompressed with another compression level later with the -X/--recompress option described further below.

  • Changed from MD4 to BLAKE3 for hashing input. This improves performance and reduces the risk of hash collisions.

  • Added checksumming of result and manifest files using the XXH3 algorithm to detect data corruption.

  • Ccache now follows the XDG base directory specification. This means that the default cache directory on Unix systems is $XDG_CACHE_HOME/ccache (with ~/.cache/ccache as the fallback if XDG_CACHE_HOME is not set) and the configuration file is $XDG_CONFIG_HOME/ccache/ccache.conf (with ~/.config/ccache/ccache.conf as the fallback). On macOS, the fallbacks are ~/Library/Caches/ccache and ~/Library/Preferences/ccache/ccache.conf. On Windows, the fallbacks are %APPDATA%/ccache and %APPDATA%/ccache/ccache.conf. Exception: If the legacy ~/.ccache directory exists, that directory is used as the default cache location and the configuration file is ~/.ccache/ccache.conf.

  • Cache statistics are now stored in files on cache level 2 to reduce lock contention when there are many parallel compilations.

  • An appropriate cache directory level structure is now chosen automatically. The cache_dir_levels (CCACHE_NLEVELS) configuration option has therefore been removed.

  • Added an experimental “inode cache” for file hashes, allowing computed hash values to be reused both within and between builds. The inode cache is off by default but can be enabled by setting inode_cache (CCACHE_INODECACHE) to true.

  • Added support for using file cloning (AKA “reflinks”) on Btrfs, XFS and APFS to copy data to and from the cache very efficiently.

  • Two measures have been implemented to make the hard link mode safer: hard-linked files are made read-only and inadvertent content changes that affect file size are detected.

  • Added a command line option -x/--show-compression which shows statistics about cache compression.

  • Added a command line option -X/--recompress which recompresses the cache data with another compression level or makes it uncompressed. If you choose to disable compression by default, or choose to use a compression level with a low compression ratio, you can recompress the cache with a higher compression level after the build or at another time when there are more CPU cycles available, for instance every night. Only files that are currently compressed with a different level than the wanted level will be recompressed.

  • Added a command line option --evict-older-than which removes cache entries older than a certain age.

  • Added a command line option -d/--directory which specifies a cache directory to operate on. It can be used instead of setting CCACHE_DIR temporarily.

  • A progress bar has been added to show the progress of time-consuming options like -c/--cleanup, -C/--clear, --evict-older-than, -x/--show-compression and -X/--recompress.

  • When supported by the CPU, a SIMD-friendly (using AVX2) algorithm is now used to scan input source code for DATE, TIME and TIMESTAMP macros. This can decrease the number of CPU cycles for a direct cache hit with up to 15% in some cases.

  • Some unnecessary stat(2) system calls are now avoided when verifying header files.

  • Compiler diagnostic messages are now always cached in color. Ccache then strips the color codes on the fly when requested explicitly by a command line option or when stderr does not refer to a TTY. This allows IDEs and terminals to share cached compilation results.

  • The configuration option compiler (CCACHE_COMPILER) now always takes effect if specified. Previously, the configuration option was only used when the compiler specified on the command line was looked up via PATH (i.e., not when an absolute path was specified).

  • Added optional logging to syslog if log_file (CCACHE_LOGFILE) is set to syslog.

  • The compiler option -fmodules is now handled in the “depend mode”. If “depend mode” is disabled the option is still considered too hard and ccache will fall back to running the compiler.

  • Ccache can now cache compilations with coverage notes (.gcno files) produced by GCC 9+ in combination with -fprofile-dir=dir.

  • realpath(3) is no longer used for normalization when computing relative paths. This makes it possible to get cache hits when the source or build directory is a symbolic link to an absolute path that includes unstable information like build IDs or timestamps.

  • Added an ignore_options (CCACHE_IGNOREOPTIONS) configuration option which makes it possible to exclude compiler options from the hash.

  • Added an absolute_paths_in_stderr (CCACHE_ABSSTDERR) configuration option which makes ccache rewrite absolute paths in compiler warnings and errors to relative.

  • Improved handling of umask. The configured umask (CCACHE_UMASK) is now only applied to files and directories in the cache directory. Previously the umask was applied to all files produced by ccache and the executed compiler.

  • Ccache is now able to share cache entries for different object file names when using -MD or -MMD.

  • Clang’s -Xclang (used by CMake for precompiled headers), -fno-pch-timestamp, -emit-pch, -emit-pth and -include-pth options are now understood.

  • Added support for the HIP (“C++ Heterogeneous-Compute Interface for Portability”) language.

  • The manifest format now allows for header files larger than 4 GiB.

  • Made it possible to once again cache compilations with DATE in the source code.

  • Added handling of the TIMESTAMP macro.

  • An absolute input source path is now rewritten to a relative path when using base_dir.

  • waitpid system calls interrupted by a signal are now handled correctly.

  • Made handling of .dwo files and interaction between -gsplit-dwarf and other -g* options more robust.

  • The “couldn’t find compiler” statistics counter is no longer incremented when ccache exits with a fatal error.

  • Failure to run a compiler_check command is no longer a fatal error.

  • Added command line options --dump-result and --extract-result for inspecting and extracting result files.

  • Added a command line option --checksum-file for debugging or evaluating the checksum algorithm.

  • Improved error message for ccache -o=K=V (trying to set a configuration option named =K).

  • Made timestamps in statistics files Y2038-proof.

  • Removed code for populating a newly created configuration file with max cache size and max files values for cache directories created by ccache versions older than 3.2 (released 2014).

  • Removed knowledge about a top-level stats file created by ccache versions older than 3.1 (released 2010).

Other improvements

  • Improved help text and documentation of command line options.

  • Improved documentation of the base_dir configuration option.

  • Improved documentation of preprocessor and direct modes.

  • Added HTML anchors to configuration options in the manual so that it is possible link to a specific option.

  • Tweaked placement of “(readonly)” in output of ccache -s.

  • Improved visibility of color output from the test suite.

  • Fixed a problem when running the test suite with Clang without a libgcov library available.

  • Fixed test suite problems on macOS.

  • Disabled hardlink tests on AFS since it lacks such support.

  • Disabled read-only tests on file systems that lack such support.

Ccache 3.7.12

Release date: 2020-10-01

Bug fixes

  • Coverage files (.gcno) produced by GCC 9+ when using -fprofile-dir=dir are now handled gracefully by falling back to running the compiler.

  • Fixed writing to log file larger than 2 GiB when running ccache compiled in 32-bit mode.


  • Improved documentation about sharing a cache on NFS.

  • Fixed test case failures with old objdump versions.

  • Fixed test case failures with GCC 4.4.

Ccache 3.7.11

Release date: 2020-07-21

Bug fixes

  • Added knowledge about -fprofile-{correction,reorder-functions,values}.

  • ccache now handles the Intel compiler option -xCODE (where CODE is a processor feature code) correctly.

  • Added support for NVCC’s -Werror and --Werror options.


  • ccache’s “Directory is not hashed if using -gz[=zlib]” tests are now skipped for GCC 6.

Ccache 3.7.10

Release date: 2020-06-22

Bug fixes

  • Improved handling of profiling options. ccache should now work correctly for profiling options like -fprofile-{generate,use}[=path] for GCC ≥ 9 and Clang as well as -fauto-profile[=path] and the Clang-specific -fprofile-instr-{generate,use}[=path] and -fprofile-sample-{use,accurate} options.

  • ccache now copies files directly from the cache to the destination file instead of via a temporary file. This avoids problems when using filenames long enough to be near the file system’s filename max limit.

  • When the hard-link mode is enabled, ccache now only uses hard links for object files, not other files like dependency files. This is because compilers unlink object files before writing to them but they don’t do that for dependency files, so the latter can become overwritten and therefore corrupted in the cache.

  • Fixed a glitch related to hard-link mode and an empty cache.

  • ccache now supports the ccache.conf file to be a symlink.

  • Temporary files are now deleted immediately on signals like SIGTERM and SIGINT instead of some time later in a cleanup phase.

  • Fixed a bug that affected ccache’s -o/--set-config option for the base_dir and cache_dir_levels keys.

Ccache 3.7.9

Release date: 2020-03-29

Bug fixes

  • Fixed replacing of /dev/null when building as root with hard link mode enabled and using -o /dev/null.

  • Removed incorrect assertion resulting in “ccache: error: Internal error in format” when using -fdebug-prefix-map=X= with X equal to $PWD.


  • Improved CUDA/NVCC support: Recognize -dc and -x cu options.

  • Improved name of temporary file used in NFS-safe unlink.

Ccache 3.7.8

Release date: 2020-03-16

Bug fixes

  • Use $PWD instead of the real CWD (current working directory) when checking for CWD in preprocessed output. This fixes a problem when $PWD includes a symlink part and the user has set hash_dir = false.

  • Rewrote the Windows version of the lockfile routines. This should mitigate several problems with the old implementation.

  • If localtime_r fails the epoch time is now logged instead of garbage.


  • Improved error message when a boolean environment variable has an invalid value.

  • Improved the regression fix in ccache 3.7.5 related to not passing compilation-only options to the preprocessor.

  • ccache’s PCH test suite now skips running the tests if it detects broken PCH compiler support.

  • Fixed unit test failure on Windows.

  • Fixed “stringop-truncation” build warning on Windows.

  • Improved “x_rename” implementation on Windows.

  • Improved removal of temporary file when rewriting absolute paths to relative in the dependency file.

  • Clarified “include_file_ctime sloppiness” in the Performance section in the manual.

Ccache 3.7.7

Release date: 2020-01-05

Bug fixes

  • Fixed a bug related to object file location in the dependency file (if using -MD or -MMD but not -MF and the build directory is not the same as the source directory then the object file location in the .d file would become incorrect). This fixes regression in ccache 3.7.5 introduced by the bug fix related to EDG-based compilers. Note that this removes support for EDG-based compilers again. (A better fix for this is planned for ccache 4.0.)

  • Removed the unify mode since it has bugs and shortcomings that are non-trivial or impossible to fix: it doesn’t work with the direct mode, it doesn’t handle C++ raw strings correctly, it can give false cache hits for .incbin directives, it’s turned off when using -g and it can make line numbers in warning messages and LINE macros incorrect.

  • mtime and ctime values are now stored in the manifest files only when sloppy_file_stat is set. This avoids adding superfluous manifest file entries on direct mode cache misses.

  • A “Result:” line is now always printed to the log.

  • The “cache miss” statistics counter will now be updated for read-only cache misses, making it consistent with the cache hit case.

Ccache 3.7.6

Release date: 2019-11-17

Bug fixes

  • The opt-in “file_macro sloppiness” mode has been removed so that the input file path now is always included in the direct mode hash. This fixes a bug that could result in false cache hits in an edge case when “file_macro sloppiness” is enabled and several identical source files include a relative header file with the same name but in different directories.

  • Statistics files are no longer lost when the filesystem of the cache is full.

  • Bail out on too hard Clang option -MJarg (in addition to the previous bailout of -MJ arg).

  • Properly handle color diagnostics in the depend mode as well.

Ccache 3.7.5

Release date: 2019-10-22

New features

  • Added support for -MF=arg (with an extra equal sign) as understood by EDG-based compilers.

Bug fixes

  • Fixed a regression in 3.7.2 that could result in a warning message instead of an error in an edge case related to usage of “-Werror”.

  • An implicit -MQ is now passed to the preprocessor only if the object file extension is non-standard. This will make it easier to use EDG-based compilers (e.g. GHS) which don’t understand -MQ. (This is a bug fix of the corresponding improvement implemented in ccache 3.4.)

  • ccache now falls back to running the real compiler instead of failing fataly if an internal temporary file is missing after compilation.

  • Fixed a crash if localtime returns null pointer in localtime_r replacement.

  • Fixed header file dependency tracking when building ccache itself.

  • Fixed warning during configure in out-of-tree build in developer mode.

Ccache 3.7.4

Release date: 2019-09-12


  • Added support for the -gz[=type] compiler option (previously ccache would think that “-gz” alone would enable debug information, thus potentially including the current directory in the hash).

  • Added support for converting paths like “/c/users/…​” into relative paths on Windows.

Ccache 3.7.3

Release date: 2019-08-17

Bug fixes

  • The cache size (which is counted in “used disk blocks”) is now correct on filesystems that use more or less disk blocks than conventional filesystems, e.g. ecryptfs or btrfs/zfs with transparent compression. This also fixes a related problem with ccache’s own test suite when run on such file systems.

  • Fixed a regression in 3.7.2 when using the compiler option “-Werror” and then “-Wno-error” later on the command line.

Ccache 3.7.2

Release date: 2019-07-19

Bug fixes

  • The compiler option -gdwarf* no longer forces “run_second_cpp = true”.

  • Added verification that the value passed to the -o/--set-config option is valid.

  • Fixed detection of precompiled headers in the depend mode.

  • Bail out on too hard Clang option -ftime-trace.

  • ccache now updates the correct stats file when adding/updating manifest files. This bug previously made the file and size statistics counters incorrect over time.

  • Fixed warnings from Clang about unused arguments during preprocessing.

  • Unknown manifest versions are now handled gracefully in --dump-manifest.

  • Fixed make check with “funny” locales.


  • Added a hint about not running when building from a release archive.

  • Mention that xsltproc is needed when building from the source repository.

Ccache 3.7.1

Release date: 2019-05-01


  • Fixed a problem when using the compiler option -MF /dev/null.

  • Long commandlines are now handled gracefully on Windows by using the @file syntax to avoid hitting the commandline size limit.

  • Fixed complaint from GCC 9’s -Werror=format-overflow when compiling ccache itself.

Ccache 3.7

Release date: 2019-04-23


  • Fixed crash when the debug mode is enabled and the output file is in a non-writable directory, e.g. when the output file is /dev/null.

  • Fixed an issue when printing very large log messages to the debug log.

  • Fixed bugs related to support for -gsplit-dwarf. Previously ccache could produce an incorrect link to the .dwo file in the .o file.

  • Compilations with /dev/null as the input file are now cached.

  • ccache has learned how to construct the object filename if no -o option is given and the source filename does not include a . or ends with a ..

  • Fixed a temporary file leak when the depend mode is enabled and the compiler produces standard error output.

  • Fixed a bug in the depend mode where a manifest hash only could be associated with one set of header dependencies.

  • Manifest files did not get marked as used on direct cache hits, so the LRU cache cleanup would incorrectly remove them eventually. This has been fixed.

  • The rewriting of absolute paths into relative paths in the dependency file has been enabled in the depend mode as well.

  • ccache now ignores unknown keys in configuration files for forward compatibility.

  • Rearranged command-line options into sections in the help text.

  • Documented the previously undocumented --dump-manifest and --hash-file options (only useful for debugging ccache itself).

  • Added missing documentation for the command-line option -k/--get-config added in ccache 3.5.

  • Renamed the --print-config command to --show-config.

  • Added a new --print-stats command that prints statistics counters in machine-parsable (tab-separated) format.

  • ccache no longer creates a missing output directory, thus mimicking the compiler behavior for -o out/obj.o when out doesn’t exist.

  • -fdebug-prefix-map=ARG, -ffile-prefix-map=ARG and -fmacro-prefix-map=ARG are now included in the hash, but only the part before “ARG”. This fixes a bug where compiler feature detection of said flags would not work correctly with ccache.

  • Bail out on too hard compiler option -gtoggle.

  • Bail out on too hard Clang options --analyze and -analyze.

  • Improved debug logging of file hashes in depend mode.

  • Improved handling of various -g* options. In particular, ccache now understands that -g0 cancels out previous -g* options.

  • Worked around a problem with Automake related to .d files when using the hard link mode.

  • Added opt-in (at configure time) support for enabling trace logs for profiling ccache itself. See doc/ in the code tree for more information

  • Removed support for Fortran 77 again. Some Fortran support was added in ccache 3.3, but the implementation did not work when Fortran modules are involved.

Ccache 3.6

Release date: 2019-01-14


  • ccache now has an opt-in “depend mode”. When enabled, ccache never executes the preprocessor, which results in much lower cache miss overhead at the expense of a lower potential cache hit rate. The depend mode is only possible to use when the compiler option -MD or -MMD is used.

  • Added support for GCC’s -ffile-prefix-map option. The -fmacro-prefix-map option is now also skipped from the hash.

  • Added support for multiple -fsanitize-blacklist arguments.

  • ccache now includes the environment variables LANG, LC_ALL, LC_CTYPE and LC_MESSAGES in the hash since they may affect localization of compiler warning messages. Set sloppiness to locale to opt out of this.

  • Fixed a problem due to Clang overwriting the output file when compiling an assembler file.

  • Clarified the manual to explain the reasoning behind the “file_macro” sloppiness setting in a better way.

  • ccache now handles several levels of nonexistent directories when rewriting absolute paths to relative.

  • A new sloppiness setting clang_index_store makes ccache skip the Clang compiler option -index-store-path and its argument when computing the manifest hash. This is useful if you use Xcode, which uses an index store path derived from the local project path. Note that the index store won’t be updated correctly on cache hits if you enable this option.

  • Rename sloppiness no_system_headers to system_headers for consistency with other options. no_system_headers can still be used as an (undocumented) alias.

  • The GCC variables “DEPENDENCIES_OUTPUT” and “SUNPRO_DEPENDENCIES” are now supported correctly.

  • The algorithm that scans for DATE_ and TIME tokens in the hashed source code now doesn’t produce false positives for tokens where DATE or TIME__ is a substring.

Ccache 3.5.1

Release date: 2019-01-02


  • Added missing getopt_long.c source file to release archive.

  • Fixed (harmless) compiler warnings when building ccache object files.

  • CFLAGS is no longer passed to the linker when linking ccache.

  • Improved development mode build flags.

Ccache 3.5

Release date: 2018-10-15


  • Added a boolean debug (CCACHE_DEBUG) configuration option. When enabled, ccache will create per-object debug files that are helpful e.g. when debugging unexpected cache misses. See also the new “Cache debugging” section in the manual.

  • Renamed CCACHE_CC to CCACHE_COMPILER (keeping the former as a deprecated alias).

  • Added a new command-line option -k/--get-config that prints the value of a config key.

  • It is now possible to let ccache hash a precomputed checksum file instead of the full content of a precompiled header. This can save time for large precompiled headers. Note that the build system needs to keep the checksum file in sync with the precompiled header for this to work.

  • Improved performance substantially when using hash_dir = false on platforms like macOS where getcwd() is slow.

  • Added “stats updated” timestamp in ccache -s output. This can be useful if you wonder whether ccache actually was used for your last build.

  • Renamed “stats zero time” to “stats zeroed” and documented it. The counter is also now only present in ccache -s output when ccache -z actually has been called.

  • The content of the -fsanitize-blacklist file is now included in the hash, so updates to the file will now correctly result in separate cache entries.

  • It’s now possible to opt out of building and installing man pages when running make install in the source repository.

  • If the compiler type can’t be detected (e.g. if it is named cc), use safer defaults that won’t trip up Clang.

  • Made the ccache test suite work on FreeBSD.

  • Added file_stat_matches_ctime option to disable ctime check if file_stat_matches is enabled.

  • Made “./configure --without-bundled-zlib” do what’s intended.

Ccache 3.4.3

Release date: 2018-09-02

Bug fixes

  • Fixed a race condition when creating the initial config file in the cache directory.

  • Bail out on too hard Clang option -MJ.

  • Bail out on too hard option -save-temps=obj.

  • Handle separate parameter to Clang option -target correctly.

  • Upgraded bundled zlib to version 1.2.11.

Ccache 3.4.2

Release date: 2018-03-25

Bug fixes

  • The cleanup algorithm has been fixed to not misbehave when files are removed by another process while the cleanup process is running. Previously, too many files could be removed from the cache if multiple cleanup processes were triggered at the same time, in extreme cases trimming the cache to a much smaller size than the configured limits.

  • Correctly hash preprocessed headers located in a “.gch directory”. Previously, ccache would not pick up changes to such precompiled headers, risking false positive cache hits.

  • Fixed build failure when using the bundled zlib sources.

  • ccache 3.3.5 added a workaround for not triggering Clang errors when a precompiled header’s dependency has an updated timestamp (but identical content). That workaround is now only applied when the compiler is Clang.

  • Made it possible to perform out-of-source builds in dev mode again.

Ccache 3.4.1

Release date: 2018-02-11

Bug fixes

  • Fixed printing of version number in ccache --version.

Ccache 3.4

Release date: 2018-02-11

New features and enhancements

  • The compiler option form --sysroot arg is now handled like the documented --sysroot=arg form.

  • Added support for caching .su files generated by GCC flag -fstack-usage.

  • ccache should now work with distcc’s “pump” wrapper.

  • The optional unifier is no longer disabled when the direct mode is enabled.

  • Added support for NVCC compiler options --compiler-bindir/-ccbin, --output-directory/-odir and --libdevice-directory/-ldir.

  • Boolean environment variable settings no longer accept the following (case-insensitive) values: 0, false, disable and no. All other values are accepted and taken to mean “true”. This is to stop users from setting e.g. CCACHE_DISABLE=0 and then expect the cache to be used.

  • Improved support for run_second_cpp = false: If combined with passing -fdirectives-only (GCC) or frewrite-includes (Clang) to the compiler, diagnostics warnings and similar will be correct.

  • An implicit -MQ is now passed to the preprocessor only if the object file extension is non-standard. This should make it easier to use EDG-based compilers (e.g. GHS) which don’t understand -MQ.

  • ccache now treats an unreadable configuration file just like a missing configuration file.

  • Documented more pitfalls with enabling hard_links (CCACHE_HARDLINK).

  • Documented caveats related to colored warnings from compilers.

Bug fixes

  • File size and number counters are now updated correctly when files are overwritten in the cache, e.g. when using CCACHE_RECACHE.

  • run_second_cpp is now forced for NVCC.

  • Fixed how the NVCC options -optf and -odir are handled.

Ccache 3.3.6

Release date: 2018-01-28

New features and enhancements

  • Improved instructions on how to get cache hits between different working directories.

Bug fixes

  • Fixed regression in ccache 3.3.5 related to the UNCACHED_ERR_FD feature.

Ccache 3.3.5

Release date: 2018-01-13

New features and enhancements

  • Documented how automatic cache cleanup works.

Bug fixes

  • Fixed a regression where the original order of debug options could be lost. This reverts the “Improved parsing of -g* options” feature in ccache 3.3.

  • Multiple -fdebug-prefix-map options should now be handled correctly.

  • Fixed matching of directories in the ignore_headers_in_manifest configuration option.

  • Fixed detection of missing argument to -opt/--options-file.

  • ccache now bails out when building a precompiled header if any of the corresponding header files has an updated timestamp. This fixes complaints from Clang.

  • Fixed a bug related to erroneously storing a dependency file with absolute paths in the cache on a preprocessed hit.

  • ccache -c/--cleanup now works like documented: it just recalculates size counters and trims the cache to not exceed the max size and file number limits. Previously, the forced cleanup took “limit_multiple” into account, so that ccache -c/--cleanup by default would trim the cache to 80% of the max limit.

  • ccache no longer ignores linker arguments for Clang since Clang warns about them.

  • Plugged a couple of file descriptor leaks.

  • Fixed a bug where ccache would skip hashing the compiler argument following a -fno-working-directory, -fworking-directory, -nostdinc, -nostdinc++, -remap or -trigraphs option in preprocessor mode.

Ccache 3.3.4

Release date: 2017-02-17

New features and enhancements

  • Documented the different cache statistics counters.

Bug fixes

  • Fixed a regression in ccache 3.3 related to potentially bad content of dependency files when compiling identical source code but with different source paths. This was only partially fixed in 3.3.2 and reverts the new “Names of included files are no longer included in the hash of the compiler’s preprocessed output” feature in 3.3.

  • Corrected statistics counter for -optf/--options-file failure.

  • Fixed undefined behavior warnings in ccache found by -fsanitize=undefined.

Ccache 3.3.3

Release date: 2016-10-26

Bug fixes

  • ccache now detects usage of .incbin assembler directives in the source code and avoids caching such compilations.

Ccache 3.3.2

Release date: 2016-09-28

Bug fixes

  • Fixed a regression in ccache 3.3 related to potentially bad content of dependency files when compiling identical source code but with different source paths.

  • Fixed a regression in ccache 3.3.1: ccache could get confused when using the compiler option -Wp, to pass multiple options to the preprocessor, resulting in missing dependency files from direct mode cache hits.

Ccache 3.3.1

Release date: 2016-09-07

Bug fixes

  • Fixed a problem in the “multiple -arch options” support introduced in 3.3. When using the direct mode (the default), different combinations of -arch options were not detected properly.

  • Fixed an issue when compiler option -Wp,-MT,path is used instead of -MT path (and similar for -MF, -MP and -MQ) and run_second_cpp (CCACHE_CPP2) is enabled.

Ccache 3.3

Release date: 2016-08-27


  • A C99-compatible compiler is now required to build ccache.

New features and enhancements

  • The configuration option run_second_cpp (CCACHE_CPP2) now defaults to true. This improves ccache’s out-of-the-box experience for compilers that can’t compile their own preprocessed output with the same outcome as if they compiled the real source code directly, e.g. newer versions of GCC and Clang.

  • The configuration option hash_dir (CCACHE_HASHDIR) now defaults to true.

  • Added a new ignore_headers_in_manifest configuration option, which specifies headers that should be ignored in the direct mode.

  • Added a new prefix_command_cpp (CCACHE_PREFIX_CPP) configuration option, which specifies one or several prefixes to add to the command line ccache uses when invoking the preprocessor.

  • Added a new limit_multiple (CCACHE_LIMIT_MULTIPLE) configuration option, which specifies how much of the cache to remove when cleaning.

  • Added a new keep_comments_cpp (CCACHE_COMMENTS) configuration option, which tells ccache not to discard the comments before hashing preprocessor output. This can be used to check documentation with -Wdocumentation.

  • Added a new sloppiness option no_system_headers, which tells ccache not to include system headers in manifest files.

  • Added a new statistics counter that tracks the number of performed cleanups due to the cache size being over the limit. The value is shown in the output of “ccache -s”.

  • Added support for relocating debug info directory using -fdebug-prefix-map. This allows for cache hits even when hash_dir is used in combination with base_dir.

  • Added a new “cache hit rate” field to the output of “ccache -s”.

  • Added support for caching compilation of assembler code produced by e.g. “gcc -S file.c”.

  • Added support for cuda including the -optf/--options-file option.

  • Added support for Fortran 77.

  • Added support for multiple -arch options to produce “fat binaries”.

  • Multiple identical -arch arguments are now handled without bailing.

  • The concatenated form of some long compiler options is now recognized, for example when using -isystemPATH instead of -isystem PATH.

  • If hard-linking is enabled and but fails (e.g. due to cross-device linking), ccache now falls back to copying instead of running the compiler.

  • Made the hash_dir option only have effect when generating debug info.

  • ccache now knows how to convert absolute paths to relative paths inside dependency files when using base_dir.

  • Improved parsing of -g* options.

  • Made ccache understand -Wp,-D* options.

  • ccache now understands the undocumented -coverage (only one dash) GCC option.

  • Names of included files are no longer included in the hash of the compiler’s preprocessed output. This leads to more potential cache hits when not using the direct mode.

  • Increased buffer size used when reading file data. This improves performance slightly.

Bug fixes

  • Bail out on too hard compiler option -P.

  • Fixed Clang test suite when running on Linux.

  • Fixed build and test for MinGW32 and Windows.

Ccache 3.2.9

Release date: 2016-09-28

Bug fixes

  • Fixed a regression in ccache 3.2.8: ccache could get confused when using the compiler option -Wp, to pass multiple options to the preprocessor, resulting in missing dependency files from direct mode cache hits.

Ccache 3.2.8

Release date: 2016-09-07

Bug fixes

  • Fixed an issue when compiler option -Wp,-MT,path is used instead of -MT path (and similar for -MF, -MP and -MQ) and run_second_cpp (CCACHE_CPP2) is enabled.

  • ccache now understands the undocumented -coverage (only one dash) GCC option.

Ccache 3.2.7

Release date: 2016-07-20

Bug fixes

  • Fixed a bug which could lead to false cache hits for compiler command lines with a missing argument to an option that takes an argument.

  • ccache now knows how to work around a glitch in the output of GCC 6’s preprocessor.

Ccache 3.2.6

Release date: 2016-07-12

Bug fixes

  • Fixed build problem on QNX, which lacks “SA_RESTART”.

  • Bail out on compiler option -fstack-usage since it creates a .su file which ccache currently doesn’t handle.

  • Fixed a bug where (due to ccache rewriting paths) the compiler could choose incorrect include files if CCACHE_BASEDIR is used and the source file path is absolute and is a symlink.

Ccache 3.2.5

Release date: 2016-04-17

New features and enhancements

  • Only pass Clang-specific -stdlib= to the preprocessor.

  • Improved handling of stale NFS handles.

  • Made it harder to misinterpret documentation of boolean environment settings' semantics.

Bug fixes

  • Include m4 files used by in the source dist archives.

  • Corrected “Performance” section in the manual regarding DATE_, TIME and FILE__ macros.

  • Fixed build on Solaris 10+ and AIX 7.

  • Fixed failure to create directories on QNX.

  • Don’t (try to) update manifest file in “read-only” and “read-only direct” modes.

  • Fixed a bug in caching of stat system calls in “file_stat_matches sloppiness mode”.

  • Fixed bug in hashing of Clang plugins, leading to unnecessary cache misses.

  • Fixed --print-config to show “pch_defines sloppiness”.

  • The man page is now built when running “make install” from Git repository sources.

Ccache 3.2.4

Release date: 2015-10-08

Bug fixes

  • Fixed build error related to zlib on systems with older make versions (regression in ccache 3.2.3).

  • Made conversion-to-bool explicit to avoid build warnings (and potential runtime errors) on legacy systems.

  • Improved signal handling: Kill compiler on SIGTERM; wait for compiler to exit before exiting; die appropriately.

  • Minor fixes related to Windows support.

  • The correct compression level is now used if compression is requested.

  • Fixed a bug where cache cleanup could be run too early for caches larger than 64 GiB on 32-bit systems.

Ccache 3.2.3

Release date: 2015-08-16

New features and enhancements

  • Added support for compiler option -gsplit-dwarf.

Bug fixes

  • Support external zlib in nonstandard directory.

  • Avoid calling exit() inside an exit handler.

  • Let exit handler terminate properly.

  • Bail out on compiler option --save-temps in addition to -save-temps.

  • Only log “Disabling direct mode” once when failing to read potential include files.

Ccache 3.2.2

Release date: 2015-05-10

New features and enhancements

  • Added support for CCACHE_COMPILERCHECK=string:<value>. This is a faster alternative to CCACHE_COMPILERCHECK=<command> if the command’s output can be precalculated by the build system.

  • Add support for caching code coverage results (compiling for gcov).

Bug fixes

  • Made hash of cached result created with and without CCACHE_CPP2 different. This makes it possible to rebuild with CCACHE_CPP2 set without having to clear the cache to get new results.

  • Don’t try to reset a nonexistent stats file. This avoids “No such file or directory” messages in the ccache log when the cache directory doesn’t exist.

  • Fixed a bug where ccache deleted Clang diagnostics after compiler failures.

  • Avoid performing an unnecessary copy of the object file on a cache miss.

  • Bail out on too hard compiler option -fmodules.

  • Bail out on too hard compiler option -fplugin=libcc1plugin (interaction with GDB).

  • Fixed build error when compiling ccache with recent Clang versions.

  • Removed signal-unsafe code from signal handler.

  • Corrected logic for when to output cached stderr.

  • Wipe the whole cached result on failure retrieving a cached file.

  • Fixed build error when compiling ccache with recent Clang versions.

Ccache 3.2.1

Release date: 2014-12-10

Bug fixes

  • Fixed regression in temporary file handling, which lead to incorrect permissions for stats, manifest and ccache.conf files in the cache.

  • CACHEDIR.TAG files are now created in the [0-9a-f] subdirectories so that ccache.conf is not lost in backups.

  • Made the default cache size suffix G, as previously documented.

  • -fdiagnostics-color=auto is now passed to the compiler even if stderr is redirected. This fixes a problem when, for instance, a configure test probes if the compiler (wrapped via ccache) supports -fdiagnostics-color=auto.

  • Added missing documentation for max_files and max_size configuration options.

Ccache 3.2

Release date: 2014-11-17

New features and enhancements

  • Added support for configuring ccache via one or several configuration files instead of via environment variables. Environment variables still have priority but are no longer the recommended way of customizing ccache behavior. See the manual for more information.

  • Added support for compiler error/warning messages with color.

  • Made creation of temporary directories and cache directories smarter to avoid unnecessary stat calls.

  • Improved efficiency of the algorithm that scans for DATE_ and TIME__ tokens in the hashed source code.

  • Added support for several binaries (separated by space) in CCACHE_PREFIX.

  • The -c option is no longer passed to the preprocessor. This fixes problems with Clang and Solaris’s C++ compiler.

  • ccache no longer passes preprocessor options like -D and -I to the compiler when compiling preprocessed output. This fixes warnings emitted by Clang.

  • Compiler options -fprofile-generate, -fprofile-arcs, -fprofile-use and -fbranch-probabilities are now handled without bailing.

  • Added support for Clang’s --serialize-diagnostic option, storing the diagnostic file (.dia) in the cache.

  • Added support for precompiled headers when using Clang.

  • Added support for Clang .pth (pretokenized header) files.

  • Changed the -x language option to use the new objective C standard for GCC and Clang.

  • On a cache miss, ccache now instructs the compiler to create the object file at the real destination and then copies the file into the cache instead of the other way around. This is needed to support compiler options like -fprofile-arcs and --serialize-diagnostics.

  • ccache now checks that included files' ctimes aren’t too new. This check can be turned off by adding include_file_ctime to the “ccache sloppiness” setting.

  • Added possibility to get cache hits based on filename, size, mtime and ctime only. On other words, source code files are not even read, only stat-ed. This operation mode is opt-in by adding file_stat_matches to the “ccache sloppiness” setting.

  • The filename part of options like -Wp,-MDfilename is no longer included in the hash since the filename doesn’t have any bearing on the result.

  • Added a “read-only direct” configuration setting, which is like the ordinary read-only setting except that ccache will only try to retrieve results from the cache using the direct mode, not the preprocessor mode.

  • The display and interpretation of cache size has been changed to use SI units.

  • Default cache size is now 5 GB (was previously 1 GiB).

  • Added configuration option to set the compression level of compressed object files in the cache.

  • Added support for @file and -@file arguments (reading options from a file).

  • -Wl, options are no longer included in the hash since they don’t affect compilation.

  • Bail out on too hard compiler option -Wp,-P.

  • Optimized MD4 calculation code on little-endian systems.

  • Various improvements and fixes on win32.

  • Improved logging to the ccache log file.

  • Added --dump-manifest command-line option for debugging purposes.

  • Added --with-bundled-zlib configure option.

  • Upgraded bundled zlib to version 1.2.8.

  • Improved to be more platform independent.

  • Made the test suite work with Clang and gcc-llvm on OS X.

  • Various other improvements of the test suite.

Bug fixes

  • Any previous .stderr is now removed from the cache when recaching.

  • Fixed an issue when handling the -arch compiler option with an argument.

  • Fixed race condition when creating the initial cache directory.

  • Fixed test suite failures when CC is a ccache-wrapped compiler.

Ccache 3.1.12

Release date: 2016-07-12

Bug fixes

  • Fixed a bug where (due to ccache rewriting paths) the compiler could choose incorrect include files if CCACHE_BASEDIR is used and the source file path is absolute and is a symlink.

Ccache 3.1.11

Release date: 2015-03-07

Bug fixes

  • Fixed bug which could result in false cache hits when source code contains '"' followed by " /*" or " //" (with variations).

  • Made hash of cached result created with and without CCACHE_CPP2 different. This makes it possible to rebuild with CCACHE_CPP2 set without having to clear the cache to get new results.

  • Don’t try to reset a nonexistent stats file. This avoids “No such file or directory” messages in the ccache log when the cache directory doesn’t exist.

Ccache 3.1.10

Release date: 2014-10-19

New features and enhancements

  • Added support for the -Xclang compiler option.

  • Improved handling of exit code of internally executed processes.

  • Zero length object files in the cache are now rejected as invalid.

  • Bail out on option -gsplit-dwarf (since it produces multiple output files).

  • Compiler option -fdebug-prefix-map is now ignored (not part of the hash). (The -fdebug-prefix-map option may be used in combination with CCACHE_BASEDIR to reuse results across different directories.)

  • Added note in documentation that --ccache-skip currently does not mean “don’t hash the following option”.

  • To enable support for precompiled headers (PCH), CCACHE_SLOPPINESS now also needs to include the new pch_defines sloppiness. This is because ccache can’t detect changes in the source code when only defined macros have been changed.

  • Stale files in the internal temporary directory (<ccache_dir>/tmp) are now cleaned up if they are older than one hour.

Bug fixes

  • Fixed path canonicalization in make_relative_path() when path doesn’t exist.

  • Fixed bug in common_dir_prefix_length(). This corrects the CCACHE_BASEDIR behavior.

  • ccache no longer tries to create the cache directory when CCACHE_DISABLE is set.

  • Fixed bug when reading manifests with a very large number of file info entries.

  • Fixed problem with logging of current working directory.

Ccache 3.1.9

Release date: 2013-01-06

Bug fixes

  • The EAGAIN signal is now handled correctly when emitting cached stderr output. This fixes a problem triggered by large error outputs from the compiler.

  • Subdirectories in the cache are no longer created in read-only mode.

  • Fixed so that ccache’s log file descriptor is not made available to the compiler.

  • Improved error reporting when failing to create temporary stdout/stderr files when executing the compiler.

  • Disappearing temporary stdout/stderr files are now handled gracefully.


  • Fixed test suite to work on ecryptfs.

Ccache 3.1.8

Release date: 2012-08-11

New features and enhancements

  • Made paths to dependency files relative in order to increase cache hits.

  • Added work-around to make ccache work with buggy GCC 4.1 when creating a pre-compiled header.

  • Clang plugins are now hashed to catch plugin upgrades.

Bug fixes

  • Fixed crash when the current working directory has been removed.

  • Fixed crash when stderr is closed.

  • Corrected a corner case when parsing backslash escapes in string literals.

  • Paths are now correctly canonicalized when computing paths relative to the base directory.


  • Made git version macro work when compiling outside of the source directory.

  • Fixed static_assert macro definition clash with GCC 4.7.

Ccache 3.1.7

Release date: 2012-01-08

Bug fixes

  • Non-writable CCACHE_DIR is now handled gracefully when CCACHE_READONLY is set.

  • Made failure to create files (typically due to bad directory permissions) in the cache directory fatal. Previously, such failures were silently and erroneously flagged as “compiler produced stdout”.

  • Both the -specs=file and --specs=file forms are now recognized.

  • Added recognition and hashing of GCC plugins specified with -fplugin=file.

  • CCACHE_COMPILERCHECK now also determines how to hash explicit specs files (-specs=file).

  • Added CPATH, C_INCLUDE_PATH and similar environment variables to the hash to avoid false cache hits when such variables have changed.

  • Corrected log message when unify mode is enabled.

  • Reverted the GCC bug compatibility introduced in ccache 3.1.5 for -MT/-MQ options with concatenated arguments. (The bug is fixed in recent GCC versions.)


  • Corrected license header for mdfour.c.

  • Improved documentation on how to fix bad object files in the cache.

Ccache 3.1.6

Release date: 2011-08-21

New features and enhancements

  • Rewrite argument to --sysroot if CCACHE_BASEDIR is used.

Bug fixes

  • Don’t crash if getcwd() fails.

  • Fixed alignment of “called for preprocessing” counter.

Ccache 3.1.5

Release date: 2011-05-29

New features and enhancements

  • Added a new statistics counter named “called for preprocessing”.

  • The original command line is now logged to the file specified with CCACHE_LOGFILE.

  • Improved error logging when system calls fail.

  • Added support for rewriting absolute paths in -F/-iframework GCC options.

  • Improved order of statistics counters in ccache -s output.

Bug fixes

  • The -MF/-MT/-MQ options with concatenated argument are now handled correctly when they are last on the command line.

  • ccache is now bug compatible with GCC for the -MT/-MQ options with concatenated arguments.

  • Fixed a minor memory leak.

  • Systems that lack (and don’t need to be linked with) libm are now supported.

Ccache 3.1.4

Release date: 2011-01-09

Bug fixes

  • Made a work-around for a bug in gzputc() in zlib 1.2.5.

  • Corrupt manifest files are now removed so that they won’t block direct mode hits.

  • ccache now copes with file systems that don’t know about symbolic links.

  • The file handle is now correctly closed on write error when trying to create a cache dir tag.

Ccache 3.1.3

Release date: 2010-11-28

Bug fixes

  • The -MFarg, -MTarg and -MQarg compiler options (i.e, without space between option and argument) are now handled correctly.


  • Portability fixes for HP-UX 11.00 and other esoteric systems.

Ccache 3.1.2

Release date: 2010-11-21

Bug fixes

  • Bail out on too hard compiler options -fdump-*.

  • NULL return values from malloc/calloc of zero bytes are now handled correctly.

  • Fixed issue when parsing precompiler output on AIX.


  • Improved documentation on which information is included in the hash sum.

  • Made the “too new header file” test case work on file systems with unsynchronized clocks.

  • The test suite now also works on systems that lack a /dev/zero.

Ccache 3.1.1

Release date: 2010-11-07

Bug fixes

  • ccache now falls back to preprocessor mode when a non-regular include file (device, socket, etc) has been detected so that potential hanging due to blocking reads is avoided.

  • CRC errors are now detected when decompressing compressed files in the cache.

  • Fixed potential object file corruption race on NFS.

  • Minor documentation corrections.

  • Fixed configure detection of ar.

  • ccache development version (set by now works with gits whose describe command doesn’t understand --dirty.


  • Minor debug log message improvements.

Ccache 3.1

Release date: 2010-09-16

New features and enhancements

  • Added support for hashing the output of a custom command (e.g. %compiler% --version) to identify the compiler instead of stat-ing or hashing the compiler binary. This can improve robustness when the compiler (as seen by ccache) actually isn’t the real compiler but another compiler wrapper.

  • Added support for caching compilations that use precompiled headers. (See the manual for important instructions regarding this.)

  • Locking of the files containing statistics counters is now done using symlinks instead of POSIX locks. This should make ccache behave a lot better on file systems where POSIX locks are slow or broken (e.g. NFS on some systems).

  • Manifest files are now updated without the need of taking locks.

  • Updates of statistics counters are now always done in one of the sub-level statistics files. This reduces lock contention, which especially improves performance on slow NFS mounts.

  • Reading and writing of statistics counters has been made forward-compatible (unknown counters are retained).

  • Files are now read without using mmap(). This has two benefits: it’s more robust against file changes during reading and it improves performance on poor systems where mmap() doesn’t use the disk cache.

  • Added .cp and .CP as known C++ suffixes.

  • Improved logging.

  • Added -install_name as an option known to take an argument. (This improves statistics when using the Darwin linker.)

Bug fixes

  • Non-fatal error messages are now never printed to stderr but logged instead.

  • Fixed a bug affecting failing commands when --ccache-skip is used.

  • Made --ccache-skip work for all options.

  • EINTR is now handled correctly.


  • Work on porting ccache to win32 (native), mostly done by Ramiro Polla. The port is not yet finished, but will hopefully be complete in some subsequent release.

  • Added a --nostats flag to the performance benchmark program.

  • Made the performance benchmark program more accurate when measuring cache hits.

  • Added a new test framework for unit tests written in C.

  • Got rid of configure-dev; dev mode is now given by presence.

  • Improved documentation on how to combine ccache with other compiler wrappers (like distcc).

  • New LICENSE.txt file with licensing and copyright details about bundled source code.

  • New AUTHORS.txt file with a list of ccache contributors.

  • New HACKING.txt file with some notes about ccache code conventions.

Ccache 3.0.1

Release date: 2010-07-15

Bug fixes

  • The statistics counter “called for link” is now correctly updated when linking with a single object file.

  • Fixed a problem with out-of-source builds.

Ccache 3.0

Release date: 2010-06-20


  • ccache is now licensed under the GNU General Public License (GPL) version 3 or later.

Upgrade notes

  • The way the hashes are calculated has changed, so you won’t get cache hits for compilation results stored by older ccache versions. Because of this, you might as well clear the old cache directory with ccache --clear if you want, unless you plan to keep using an older ccache version.

New features and enhancements

  • ccache now has a “direct mode” where it computes a hash of the source code (including all included files) and compiler options without running the preprocessor. By not running the preprocessor, CPU usage is reduced; the speed is somewhere between 1 and 5 times that of ccache running in traditional mode, depending on the circumstances. The speedup will be higher when I/O is fast (e.g., when files are in the disk cache). The direct mode can be disabled by setting CCACHE_NODIRECT.

  • Support has been added for rewriting absolute paths to relative paths when hashing, in order to increase cache hit rate when building the same source code in different directories even when compiling with -g and when using absolute include directory paths. This is done by setting the CCACHE_BASEDIR environment variable to an absolute path that specifies which paths to rewrite.

  • Object files are now optionally stored compressed in the cache. The runtime cost is negligible, and more files will fit in the ccache directory and in the disk cache. Set CCACHE_COMPRESS to enable object file compression. Note that you can’t use compression in combination with the hard link feature.

  • A CCACHE_COMPILERCHECK option has been added. This option tells ccache what compiler-identifying information to hash to ensure that results retrieved from the cache are accurate. Possible values are: none (don’t hash anything), mtime (hash the compiler’s mtime and size) and content (hash the content of the compiler binary). The default is mtime.

  • It is now possible to specify extra files whose contents should be included in the hash sum by setting the CCACHE_EXTRAFILES option.

  • Added support for Objective-C and Objective-C\\. The statistics counter “not a C/C++ file” has been renamed to “unsupported source language”.

  • Added support for the -x compiler option.

  • Added support for long command-line options.

  • A CACHEDIR.TAG file is now created in the cache directory. See

  • Messages printed to the debug log (specified by CCACHE_LOGFILE) have been improved.

  • You can relax some checks that ccache does in direct mode by setting CCACHE_SLOPPINESS. See the manual for more information.

  • CCACHE_TEMPDIR no longer needs to be on the same filesystem as CCACHE_DIR.

  • The default value of CCACHE_TEMPDIR has been changed to $CCACHE_DIR/tmp to avoid cluttering the top directory.

  • Temporary files that later will be moved into the cache are now created in the cache directory they will end up in. This makes ccache more friendly to Linux’s directory layout.

  • Improved the test suite and added tests for most of the new functionality. It’s now also possible to specify a subset of tests to run.

  • Standard error output from the compiler is now only stored in the cache if it’s non-empty.

  • If the compiler produces no object file or an empty object file, but gives a zero exit status (could be due to a file system problem, a buggy program specified by CCACHE_PREFIX, etc.), ccache copes with it properly.

  • Added installcheck and distcheck make targets.

  • Clarified cache size limit options' and cleanup semantics.

  • Improved display of cache max size values.

  • The following options are no longer hashed in the preprocessor mode: -imacros, -imultilib, -iprefix, -iquote, -isysroot, -iwithprefix, -iwithprefixbefore, -nostdinc, -nostdinc++ and -U.

Bug fixes

  • Various portability improvements.

  • Improved detection of home directory.

  • User-defined CPPFLAGS and LDFLAGS are now respected in the Makefile.

  • Fixed NFS issues.

  • Computation of the hash sum has been improved to decrease the risk of hash collisions. For instance, the compiler options -X -Y and -X-Y previously contributed equally to the hash sum.

  • Bail out on too hard compiler options --coverage, -fprofile-arcs, -fprofile-generate, -fprofile-use, -frepo, -ftest-coverage and -save-temps. Also bail out on @file style options.

  • Errors when using multiple -arch compiler options are now noted as “unsupported compiler option”.

  • -MD/-MMD options without -MT/-MF are now handled correctly.

  • The -finput-charset option is now handled correctly.

  • Added support for -Wp,-MD and -Wp,-MMD options.

  • The compiler options -Xassembler, -b, -G and -V are now correctly recognized as taking an argument.

  • Debug information containing line numbers of predefined and command-line macros (enabled with the compiler option -g3) will now be correct.

  • Corrected LRU cleanup handling of object files.

  • utimes() is now used instead of utime() when available.

  • Non-writable cache directories are now handled gracefully.

  • Corrected documentation about sharing the cache directory.

  • Fixed compilation warnings from GCC 4.3.

  • The command specified by CCACHE_PREFIX is no longer part of the hash.

  • Fixed bad memory access spotted by Valgrind.

  • Fixed a bug in x_realloc.

  • Freed memory is no longer referenced when compiling a .i/.ii file and falling back to running the real compiler.

  • The test suite is now immune to external values of the CCACHE_* environment variables.

  • Improved detection of recursive invocation.

  • The ccache binary is now not unconditionally stripped when installing.

  • Statistics counters are now correctly updated for -E option failures and internal errors.