Cross and Native File reference
Cross and native files are nearly identical, but not completely. This is the documentation on the common values used by both, for the specific values of one or the other see the cross compilation and native environments.
The following sections are allowed:
String and list concatenation is supported using the
+ operator, joining paths
is supported using the
Entries defined in the
[constants] section can be used in any other section
(they are always parsed first), entries in any other section can be used only
within that same section and only after it has been defined.
[constants] toolchain = '/toolchain' common_flags = ['--sysroot=' + toolchain / 'sysroot'] [properties] c_args = common_flags + ['-DSOMETHING'] cpp_args = c_args + ['-DSOMETHING_ELSE'] [binaries] c = toolchain / 'gcc'
This can be useful with cross file composition as well. A generic cross file could be composed with a platform specific file where constants are defined:
# aarch64.ini [constants] arch = 'aarch64-linux-gnu'
# cross.ini [binaries] c = arch + '-gcc' cpp = arch + '-g++' strip = arch + '-strip' pkgconfig = arch + '-pkg-config' ...
This can be used as
meson setup --cross-file aarch64.ini --cross-file cross.ini builddir.
Note that file composition happens before the parsing of values. The example
below results in
# file1.ini: [constants] a = 'Foo' b = a + 'World'
#file2.ini: [constants] a = 'Hello'
The example below results in an error when file1.ini is included before file2.ini
b would be defined before
# file1.ini: [constants] b = a + 'World'
#file2.ini: [constants] a = 'Hello'
The binaries section contains a list of binaries. These can be used
internally by meson, or by the
Compilers and linkers are defined here using
<lang>_ld is special because it is compiler specific. For compilers like
gcc and clang which are used to invoke the linker this is a value to pass to
their "choose the linker" argument (-fuse-ld= in this case). For compilers
like MSVC and Clang-Cl, this is the path to a linker for meson to invoke,
lld-link.exe. Support for ls is new in 0.53.0
changed in 0.53.1 the
ld variable was replaced by
<lang>_ld, because it
*regressed a large number of projects. in 0.53.0 the
ld variable was used
c = '/usr/bin/clang' c_ld = 'lld' sed = 'C:\\program files\\gnu\\sed.exe' llvm-config = '/usr/lib/llvm8/bin/llvm-config'
c = '/usr/bin/i586-mingw32msvc-gcc' cpp = '/usr/bin/i586-mingw32msvc-g++' c_ld = 'gold' cpp_ld = 'gold' ar = '/usr/i586-mingw32msvc/bin/ar' strip = '/usr/i586-mingw32msvc/bin/strip' pkgconfig = '/usr/bin/i586-mingw32msvc-pkg-config'
An incomplete list of internally used programs that can be overridden here is:
- wx-config (or wx-3.0-config or wx-config-gtk)
Paths and Directories
As of 0.50.0 paths and directories such as libdir can be defined in the native file in a paths section
[paths] libdir = 'mylibdir' prefix = '/my prefix'
These values will only be loaded when not cross compiling. Any arguments on the
command line will override any options in the native file. For example, passing
--libdir=otherlibdir would result in a prefix of
/my prefix and a libdir of
New in native files in 0.54.0, always in cross files.
In addition to special data that may be specified in cross files, this
section may contain random key value pairs accessed using the
New for native files in 0.54.0
The properties section can contain any variable you like, and is accessed via
Loading multiple machine files
Native files allow layering (cross files can be layered since meson 0.52.0). More than one native file can be loaded, with values from a previous file being overridden by the next. The intention of this is not overriding, but to allow composing native files. This composition is done by passing the command line argument multiple times:
meson setup builddir/ --cross-file first.ini --cross-file second.ini --cross-file thrid.ini
In this case
first.ini will be loaded, then
second.ini, with values from
first.ini, and so on.
For example, if there is a project using C and C++, python 3.4-3.7, and LLVM 5-7, and it needs to build with clang 5, 6, and 7, and gcc 5.x, 6.x, and 7.x; expressing all of these configurations in monolithic configurations would result in 81 different native files. By layering them, it can be expressed by just 12 native files.
The results of the search are