INSTALL.md

Ccache installation

Prerequisites

To build ccache you need:

• CMake 3.15 or newer.
• A C++17 compiler. See Supported platforms, compilers and languages for details.
• A C99 compiler.
• Various software libraries, see Dependencies below.

Optional:

• GNU Bourne Again SHell (bash) for tests.
• Asciidoctor to build the HTML documentation.
• Python to debug and run the performance test suite.

See also CI configurations for regularly tested build setups, including cross-compilation and dependencies required in Debian/Ubuntu environments.

Software library dependencies

How to locate or retrieve

The CMake variable DEPS can be set to select how software library dependencies should be located or retrieved:

• AUTO (the default): Use dependencies from the local system if available. Otherwise: Use bundled dependencies if available. Otherwise: Download dependencies from the internet (dependencies will then be linked statically).
• DOWNLOAD: Use bundled dependencies if available. Otherwise: Download dependencies from the internet (dependencies will then be linked statically).
• LOCAL: Use dependencies from the local system if available. Otherwise: Use bundled dependencies if available.

Dependencies

• BLAKE3¹
• cpp-httplib¹
• doctest² (optional, disable with -D ENABLE_TESTING=OFF)
• fmt²
• hiredis² (optional, disable with -D REDIS_STORAGE_BACKEND=OFF)
• span-lite¹
• tl-expected¹
• xxhash²
• Zstandard²

Tips

• To make CMake search for libraries in a custom location, use -D CMAKE_PREFIX_PATH=/some/custom/path.
• To link libraries statically, pass -D STATIC_LINK=ON to CMake (this is the default on Windows). Alternatively, use -D EXAMPLE_LIBRARY=/path/to/libexample.a to link statically with libexample.

Installation

Here is a typical way to build and install ccache:

mkdir build
cd build
cmake -D CMAKE_BUILD_TYPE=Release ..
make
make install

You can set the installation directory to e.g. /usr by adding -D CMAKE_INSTALL_PREFIX=/usr to the CMake command. You can set the directory where the system configuration file should be located to e.g. /etc by adding -D CMAKE_INSTALL_SYSCONFDIR=/etc.

There are two different ways to use ccache to cache a compilation:

1. Prefix your compilation command with ccache. This method is most convenient if you just want to try out ccache or wish to use it for some specific projects.

2. Let ccache masquerade as the compiler. This method is most useful when you wish to use ccache for all your compilations. To do this, create a symbolic link to ccache named as the compiler. For example, here is how to set up ccache to masquerade as gcc and g++:

   cp ccache /usr/local/bin/
   ln -s ccache /usr/local/bin/gcc
   ln -s ccache /usr/local/bin/g++

   On platforms that don't support symbolic links you can simply copy ccache to the compiler name instead for a similar effect:

   cp ccache /usr/local/bin/gcc
   cp ccache /usr/local/bin/g++

   And so forth. This will work as long as the directory with symbolic links or ccache copies comes before the directory with the compiler (typically /usr/bin) in PATH.

Footnotes

1. A bundled version will be used if missing locally. ↩ ↩² ↩³ ↩⁴

2. A downloaded version will be used if missing locally. ↩ ↩² ↩³ ↩⁴ ↩⁵