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Reference manual
This page lists functions and methods available in Meson scripts. For more in-depth documentation on how to use them, refer to the manual. For more basic information about how Meson works, take a look at the syntax reference.
The following functions are available in build files. Click on each to see the description and usage. The objects returned by them are list afterwards.
- add_global_arguments
- add_global_link_arguments
- add_languages
- add_project_arguments
- add_project_link_arguments
- add_test_setup
- benchmark
- build_target
- configuration_data
- configure_file
- custom_target
- declare_dependency
- dependency
- error
- environment
- executable
- find_program
- find_library
- files
- generator
- get_option
- get_variable
- import
- include_directories
- install_data
- install_headers
- install_man
- install_subdir
- is_variable
- jar
- join_paths
- library
- message
- project
- run_command
- run_target
- set_variable
- shared_library
- shared_module
- static_library
- subdir
- subproject
- test
- vcs_tag
These are built-in objects that are always available.
These are objects returned by the functions listed above.
- build target object
- compiler object
- run result object
- configuration data object
- dependency object
- external program object
- environment object
- external library object
- generator object
- subproject object
void add_global_arguments(arg1, arg2, ...)
Adds the positional arguments to the compiler command line for the language specified in language
keyword argument. Note that there is no way to remove an argument set in this way. If you have an argument that is only used in a subset of targets, you have to specify it in per-target flags.
The arguments are used in all compiler invocations with the exception of compile tests, because you might need to run a compile test with and without the argument in question. For this reason only the arguments explicitly specified are used during compile tests.
Note: Usually you should use add_project_arguments
instead, because that works even when you project is used as a subproject.
Note: You must pass always arguments individually arg1, arg2, ...
rather than as a string 'arg1 arg2', ...
void add_global_link_arguments(*arg1*, *arg2*, ...)
Like add_global_arguments
but the arguments are passed to the linker.
add_languages(*langs*)
Add support for new programming languages. Equivalent to having them in the project
declaration. This function is usually used to add languages that are only used on some platforms like this:
project('foobar', 'c')
if compiling_for_osx
add_languages('objc')
endif
Takes one keyword argument, required
. It defaults to true
, which means that if any of the languages specified is not found, Meson will halt. Returns true if all languages specified were found and false otherwise.
void add_project_arguments(arg1, arg2, ...)
This function behaves in the same way as add_global_arguments
except that the arguments are only used for the current project, they won't be used in any other subproject.
void add_project_link_arguments(*arg1*, *arg2*, ...)
Like add_project_arguments
but the arguments are passed to the linker.
void add_test_setup(*name*, ...)
Add a custom test setup that can be used to run the tests with a custom setup, for example under Valgrind. The keyword arguments are the following:
-
exe_wrapper
a list containing the wrapper command or script followed by the arguments to it -
gdb
iftrue
, the tests are also run undergdb
-
timeout_multiplier
a number to multiply the test timeout with -
env
an environment object to use a custom environment
To use the test setup, run mesontest --setup=*name*
inside the build dir.
Note that all these options are also available while running the mesontest
script for running tests instead of ninja test
or msbuild RUN_TESTS.vcxproj
, etc depending on the backend.
void benchmark(name, executable, ...)
Creates a benchmark item that will be run when the benchmark target is run. The behaviour of this function is identical to test
with the exception that there is no is_parallel
keyword, because benchmarks are never run in parallel.
Creates a build target whose type can be set dynamically with the target_type
keyword argument. This declaration:
executable(<arguments and keyword arguments>)
is equivalent to this:
build_target(<arguments and keyword arguments>, target_type : 'executable')
The object returned by build_target
and all convenience wrappers for build_target
such as executable
and library
has methods that are documented in the object methods section below.
configuration_data_object = configuration_data()
Creates an empty configuration object. You should add your configuration with its method calls and finally use it in a call to configure_file
.
generated_file = configure_file(...)
This function can run in two modes depending on the keyword arguments passed to it.
When a configuration_data()
object is passed to the configuration:
keyword argument, it takes a template file as the input:
(optional) and produces the output:
(required) by substituting values from the configuration data as detailed in the configuration file documentation.
When a list of strings is passed to the command:
keyword argument, it takes any source or configured file as the input:
and assumes that the output:
is produced when the specified command is run.
These are all the supported keyword arguments:
-
input
the input file name. If it's not specified in configuration mode, all the variables in theconfiguration:
object (see above) are written to theoutput:
file. -
output
the output file name. In configuration mode, the permissions of the input file (if it is specified) are copied to the output file. -
configuration
as explained above, this is where you pass the configuration data object as returned byconfiguration_data()
-
command
as explained above, if specified, Meson does not create the file itself but rather runs the specified command, which allows you to do fully custom file generation -
install_dir
the subdirectory to install the generated file to (e.g.share/myproject
), if omitted the file is not installed.
ctarget custom_target(*name*, ...)
Create a custom top level build target. The only positional argument is the name of this target and the keyword arguments are the following.
-
input
list of source files -
output
list of output files -
command
command to run to create outputs from inputs. The command may be strings or the return offind_program()
orexecutable()
(note: always specify commands in array form['commandname', '-arg1', '-arg2']
rather than as a string'commandname -arg1 -arg2'
as the latter will not work) -
install
when true, this target is installed during the install step -
install_dir
directory to install to -
build_always
iftrue
this target is always considered out of date and is rebuilt every time, useful for things such as build timestamps or revision control tags -
capture
, there are some compilers that can't be told to write their output to a file but instead write it to standard output. When this argument is set to true, Meson capturesstdout
and writes it to the target file. Note that your command argument list may not contain@OUTPUT@
when capture mode is active. -
depends
specifies that this target depends on the specified target(s), even though it does not take any of them as a command line argument. This is meant for cases where you have a tool that e.g. does globbing internally. Usually you should just put the generated sources as inputs and Meson will set up all dependencies automatically. -
depend_files
files (string
,files()
, orconfigure_file()
) that this target depends on but are not listed in thecommand
kwarg. Useful for adding regen dependencies. -
depfile
is a dependency file that the command can write listing all the additional files this target depends on, for example a C compiler would list all the header files it included, and a change in any one of these files triggers a recompilation -
build_by_default
(added 0.38.0) causes, when set to true, to have this target be built by default, that is, when invoking plainninja
; the default value is false
The list of strings passed to the command
kwarg accept the following special string substitutions:
-
@INPUT@
the full path to the input passed toinput
. If more than one input is specified, all of them will be substituted as separate arguments only if the command uses'@INPUT@'
as a standalone-argument. For instance, this would not work:command : ['cp', './@INPUT@']
, but this would:command : ['cp', '@INPUT@']
. -
@OUTPUT@
the full path to the output passed tooutput
. If more than one outputs are specified, the behaviour is the same as@INPUT@
. -
@INPUT0@
@INPUT1@
...
the full path to the input with the specified array index ininput
-
@OUTPUT0@
@OUTPUT1@
...
the full path to the output with the specified array index inoutput
-
@OUTDIR@
the full path to the directory where the output(s) must be written -
@DEPFILE@
the full path to the dependency file passed todepfile
dependency_object declare_dependency(...)
This function returns a dependency object that behaves like the return value of dependency
but is internal to the current build. The main use case for this is in subprojects. This allows a subproject to easily specify how it should be used. This makes it interchangeable with the same dependency that is provided externally by the system. This function has three keyword arguments.
-
include_directories
, the directories to add to header search path -
link_with
, libraries to link against -
sources
, sources to add to targets (or generated header files that should be built before sources including them are built) -
dependencies
, other dependencies needed to use this dependency -
compile_args
, compile arguments to use -
link_args
, link arguments to use -
version
, the version of this depency, such as1.2.3
dependency_object dependency(*dependency_name*, ...)
Finds an external dependency with the given name with pkg-config
if possible and with fallback detection logic otherwise. Dependency supports the following keyword arguments.
-
modules
specifies submodules to use for dependencies such as Qt5 or Boost. -
required
, when set to false, Meson will proceed with the build even if the dependency is not found -
version
, specifies the required version, a string containing a comparison operator followed by the version string, examples include>1.0.0
,<=2.3.5
or3.1.4
for exact matching. (Added 0.37.0) You can also specify multiple restrictions by passing a list to this kwarg, such as:['>=3.14.0', '<=4.1.0']
. -
native
if set totrue
, causes Meson to find the dependency on the build machine system rather than the host system (i.e. where the cross compiled binary will run on), usually only needed if you build a tool to be used during compilation. -
static
tells the dependency provider to try to get static libraries instead of dynamic ones (note that this is not supported by all dependency backends) -
fallback
specifies a subproject fallback to use in case the dependency is not found in the system. The value is an array['subproj_name', 'subproj_dep']
where the first value is the name of the subproject and the second is the variable name in that subproject that contains the value ofdeclare_dependency
. -
default_options
(added 0.37.0) an array of option values that override those set in the project'sdefault_options
invocation (likedefault_options
inproject()
, they only have effect when Meson is run for the first time, and command line arguments override any default options in build files)
The returned object also has methods that are documented in the object methods section below.
void error(message)
Print the argument string and halts the build process.
environment_object environment()
Returns an empty environment variable object.
exe executable(*exe_name*, *sources*, ...)
Creates a new executable. The first argument specifies its name and the remaining positional arguments define the source files to use. They can be of the following types:
- Strings relative to the current source directory
-
files()
objects defined in any preceding build file - The return value of configure-time generators such as
configure_file()
- The return value of build-time generators such as
custom_target()
orgenerator.process()
These source files can be sources, objects, libraries, or any other file. Meson will automatically categorize them based on the extension and use them accordingly. For instance, sources (.c
, .cpp
, .vala
, .rs
, etc) will be compiled, objects (.o
, .obj
) and libraries (.so
, .dll
, etc) will be linked, and all other files (headers, unknown extensions, etc) will be ignored. Meson will still create a build-time dependency on all source files, which is useful with generated files.
Executable supports the following keyword arguments. Note that just like the positional arguments above, these keyword arguments can also be passed to shared and static libraries.
-
link_with
, one or more shared or static libraries (built by this project) that this target should be linked with -
<languagename>_pch
precompiled header file to use for the given language -
<languagename>_args
compiler flags to use for the given language; eg:cpp_args
for C++ -
link_args
flags to use during linking. You can use unix-style flags here for all platforms. -
link_depends
an extra file in the source tree that the link step depends on such as a symbol visibility map. The purpose is to automatically trigger a re-link (but not a re-compile) of the target when this file changes. -
include_directories
one or more objects created with theinclude_directories
function -
dependencies
one or more objects created withdependency
orfind_library
(for external deps) ordeclare_dependency
(for deps built by the project) -
gui_app
when set to true flags this target as a GUI application on platforms where this makes a difference (e.g. Windows) -
extra_files
are not used for the build itself but are shown as source files in IDEs that group files by targets (such as Visual Studio) -
install
, when set to true, this executable should be installed -
install_rpath
a string to set the target's rpath to after install (but not before that) -
install_dir
override install directory for this file. The value is relative to theprefix
specified. F.ex, if you want to install plugins into a subdir, you'd use something like this:install_dir : get_option('libdir') + '/projectname-1.0'
. -
objects
list of prebuilt object files (usually for third party products you don't have source to) that should be linked in this target, never use this for object files that you build yourself. -
name_suffix
the string that will be used as the extension for the target by overriding the default. By default on Windows this isexe
and on other platforms it is omitted. -
build_by_default
causes, when set to true, to have this target be built by default, that is, when invoking plainninja
, the default value is true for all built target types, since 0.38.0
The list of sources
, objects
, and dependencies
is always flattened, which means you can freely nest and add lists while creating the final list. As a corollary, the best way to handle a 'disabled dependency' is by assigning an empty list []
to it and passing it like any other dependency to the dependencies:
kwarg.
The returned object also has methods that are documented in the object methods section below.
This function is deprecated and in the 0.31.0 release it was moved to the compiler object as obtained from meson.get_compiler(lang)
.
program find_program(program_name1, program_name2, ...)
program_name1
here is a string that can be an executable or script to be searched for in PATH
, or a script in the current source directory.
Meson will also autodetect scripts with a shebang line and run them with the executable/interpreter specified in it both on Windows (because the command invocator will reject the command otherwise) and UNIXes (if the script file does not have the executable bit set). Hence, you must not manually add the interpreter while using this script as part of a list of commands.
program_name2
and later positional arguments are used as fallback strings to search for. This is meant to be used for cases where the program may have many alternative names, such as foo
and foo.py
. The function will check for the arguments one by one and the first one that is found is returned. Meson versions earlier than 0.37.0 only accept one argument.
If none of the programs are found, Meson will abort. You can tell it not to by setting the keyword argument required
to false, and then use the .found()
method on the returned object to check whether it was found or not.
The returned object also has methods that are documented in the object methods section below.
file_array files(list_of_filenames)
This command takes the strings given to it in arguments and returns corresponding File objects that you can use as sources for build targets. The difference is that file objects remember the subdirectory they were defined in and can be used anywhere in the source tree. As an example suppose you have source file foo.cpp
in subdirectory bar1
and you would like to use it in a build target that is defined in bar2
. To make this happen you first create the object in bar1
like this:
foofile = files('foo.cpp')
Then you can use it in bar2
like this:
executable('myprog', 'myprog.cpp', foofile, ...)
Meson will then do the right thing.
generator_object gen(*executable*, ...)
See also: custom_target
This function creates a generator object that can be used to run custom compilation commands. The only positional argument is the executable to use. It can either be a self-built executable or one returned by find_program. Keyword arguments are the following:
-
arguments
a list of template strings that will be the command line arguments passed to the executable -
output
a template string (or list of template strings) defining how an output file name is (or multiple output names are) generated from a single source file name -
depfile
is a template string pointing to a dependency file that a generator can write listing all the additional files this target depends on, for example a C compiler would list all the header files it included, and a change in any one of these files triggers a recompilation
The returned object also has methods that are documented in the object methods section below.
The template strings passed to all the above kwargs accept the following special substitutions:
-
@PLAINNAME@
: the complete input file name, e.g:foo.c
becomesfoo.c
(unchanged) -
@BASENAME@
: the base of the input filename, e.g.:foo.c.y
becomesfoo.c
(extension is removed)
Each string passed to the outputs
kwarg must be constructed using one or both of these two substitutions.
In addition to the above substitutions, the arguments
kwarg also accepts the following:
-
@OUTPUT@
: the full path to the output file -
@INPUT@
: the full path to the input file -
@SOURCE_DIR@
: the full path to the root of the source tree -
@BUILD_DIR@
: the full path to the root of the build dir where the output will be placed
NOTE: Generators should only be used for outputs that will only be used as inputs for a build target or a custom target. When you use the processed output of a generator in multiple targets, the generator will be run multiple times to create outputs for each target. Each output will be created in a target-private directory @BUILD_DIR@
.
If you want to generate files for general purposes such as for generating headers to be used by several sources, or data that will be installed, and so on, use a custom_target
instead.
value get_option(option_name)
Obtains the value of the [project build option](Build options) specified in the positional argument.
value get_variable(variable_name, fallback)
This function can be used to dynamically obtain a variable. res = get_variable(varname, fallback)
takes the value of varname
(which must be a string) and stores the variable of that name into res
. If the variable does not exist, the variable fallback
is stored to res
instead. If a fallback is not specified, then attempting to read a non-existing variable will cause a fatal error.
module_object import(module_name)
Imports the given extension module. Returns an opaque object that can be used to call the methods of the module. Here's an example for a hypothetical testmod
module.
tmod = import('testmod')
tmod.do_something()
include_object include_directories(directory_names, ...)
Returns an opaque object which contains the directories (relative to the current directory) given in the positional arguments. The result can then be passed to the include_directories:
keyword argument when building executables or libraries. You can use the returned object in any subdirectory you want, Meson will make the paths work automatically.
Note that this function call itself does not add the directories into the search path, since there is no global search path. For something like that, see add_project_arguments()
.
Each directory given is converted to two include paths: one that is relative to the source root and one relative to the build root.
For example, with the following source tree layout in /home/user/project.git
:
meson.build
:
project(...)
subdir('include')
subdir('src')
...
include/meson.build
:
inc = include_directories('.')
...
src/meson.build
:
sources = [...]
executable('some-tool', sources,
include_directories : inc,
...)
...
If the build tree is /tmp/build-tree
, the following include paths will be used in the executable()
call: -I/tmp/build-tree/src/include -I/home/user/project.git/src/include
.
This function has one keyword argument is_system
which, if set, flags the specified directories as system directories. This means that they will be used with the -isystem
compiler argument rather than -I
on compilers that support this flag (in practice everything except Visual Studio).
void install_data(list_of_files, ...)
Installs files from the source tree that are listed as positional arguments. The following keyword arguments are supported:
-
install_dir
the absolute or relative path to the installation directory. If this is a relative path, it is assumed to be relative to the prefix. -
install_mode
specify the file mode in symbolic format and optionally the owner/uid and group/gid for the installed files. For example:install_mode: 'rw-r--r--'
for just the file modeinstall_mode: ['rw-r--r--', 'nobody', 'nobody']
for the file mode and the user/groupinstall_mode: ['rw-r-----', 0, 0]
for the file mode and uid/gid
To leave any of these three as the default, specify false
.
void install_headers(list_of_headers, ...)
Installs the specified header files from the source tree into the system header directory (usually /{prefix}/include
) during the install step. This directory can be overridden by specifying it with the install_dir
keyword argument. If you just want to install into a subdirectory of the system header directory, then use the subdir
argument. As an example if this has the value myproj
then the headers would be installed to /{prefix}/include/myproj
.
For example, this will install common.h
and kola.h
into /{prefix}/include
:
install_headers('common.h', 'proj/kola.h')
This will install common.h
and kola.h
into /{prefix}/include/myproj
:
install_headers('common.h', 'proj/kola.h', subdir : 'myproj')
This will install common.h
and kola.h
into /{prefix}/cust/myproj
:
install_headers('common.h', 'proj/kola.h', install_dir : 'cust', subdir : 'myproj')
void install_man(list_of_manpages, ...)
Installs the specified man files from the source tree into system's man directory during the install step. This directory can be overridden by specifying it with the install_dir
keyword argument.
void install_subdir(subdir_name)
Installs the entire given subdirectory and its contents from the source tree to the location specified by the keyword argument install_dir
. Note that due to implementation issues this command deletes the entire target dir before copying the files, so you should never use install_subdir
to install into two overlapping directories (such as foo
and foo/bar
) because if you do the behaviour is undefined.
bool is_variable(varname)
Returns true if a variable of the given name exists and false otherwise.
jar_object jar(name, list_of_sources, ...)
Build a jar from the specified Java source files. Keyword arguments are the same as executable's, with the addition of main_class
which specifies the main class to execute when running the jar with java -jar file.jar
.
string join_paths(string1, string2, ...)
Joins the given strings into a file system path segment. For example join_paths('foo', 'bar')
results in foo/bar
. If any one of the individual segments is an absolute path, all segments before it are dropped. That means that join_paths('foo', '/bar')
returns /bar
.
Added 0.36.0
buildtarget library(library_name, list_of_sources, ...)
Builds a library that is either static or shared depending on the value of default_library
user option. You should use this instead of shared_library
or static_library
most of the time. This allows you to toggle your entire project (including subprojects) from shared to static with only one option.
The keyword arguments for this are the same as for executable
with the following addition:
-
name_prefix
the string that will be used as the suffix for the target by overriding the default (only used for libraries). By default this islib
on all platforms and compilers except with MSVC where it is omitted.
static_library
and shared_library
also accept this keyword argument.
void message(text)
This function prints its argument to stdout.
void project(project_name, list_of_languages, ...)
The first argument to this function must be a string defining the name of this project. It must be followed by one or more programming languages that the project uses. Supported values for languages are c
, cpp
(for C++
), objc
, objcpp
, fortran
, java
, cs
(for C#
) and vala
.
The project name can be any string you want, it's not used for anything except descriptive purposes. However since it is written to e.g. the dependency manifest is usually makes sense to have it be the same as the project tarball or pkg-config name. So for example you would probably want to use the name libfoobar instead of The Foobar Library.
Project supports the following keyword arguments.
-
version
, which is a free form string describing the version of this project. You can access the value in your Meson build files withmeson.project_version()
. -
subproject_dir
specifies the top level directory name that holds Meson subprojects. This is only meant as a compatibility option for existing code bases that house their embedded source code in a custom directory. All new projects should not set this but instead use the default value. It should be noted that this keyword argument is ignored inside subprojects. There can be only one subproject dir and it is set in the top level Meson file. -
meson_version
takes a string describing which Meson version the project requires. Usually something like>0.28.0
. Similarly you can specify the license(s) the code is under with thelicense
keyword argument. Usually this would be something likelicense : 'GPL2+'
, but if the code has multiple licenses you can specify them as an array like this:license : ['proprietary', 'GPL3']
. Note that the text is informal and is only written to the dependency manifest. Meson does not do any license validation, you are responsible for verifying that you abide by all licensing terms. -
default_options
takes an array of strings. The strings are in the formkey=value
and have the same format as options tomesonconf
. For example to set the default project type you would set this:default_options : ['buildtype=debugoptimized']
. Note that these settings are only used when running Meson for the first time. Global options such asbuildtype
can only be specified in the master project, settings in subprojects are ignored. Project specific options are used normally even in subprojects.
runresult run_command(command, list_of_args)
Runs the command specified in positional arguments. Returns an opaque object containing the result of the invocation. The script is run from an unspecified directory, and Meson will set three environment variables MESON_SOURCE_ROOT
, MESON_BUILD_ROOT
and MESON_SUBDIR
that specify the source directory, build directory and subdirectory the target was defined in, respectively.
buildtarget run_target(target_name, ...)
This function creates a new top-level target that runs a specified command with the specified arguments. Like all top-level targets, this integrates with the selected backend. For instance, with Ninja you can run it as ninja target_name
.
The script is run from an unspecified directory, and Meson will set three environment variables MESON_SOURCE_ROOT
, MESON_BUILD_ROOT
and MESON_SUBDIR
that specify the source directory, build directory and subdirectory the target was defined in, respectively.
-
command
is a list containing the command to run and the arguments to pass to it. Each list item may be a string or a target. For instance, passing the return value ofexecutable()
as the first item will run that executable, or passing a string as the first item will find that command inPATH
and run it. -
depends
is a list of targets that this target depends on but which are not listed in the command array (because, for example, the script does file globbing internally)
void set_variable(variable_name, value)
Assigns a value to the given variable name. Calling set_variable('foo', bar)
is equivalent to foo = bar
.
buildtarget shared_library(library_name, list_of_sources, ...)
Builds a shared library with the given sources. Positional and keyword arguments are the same as for library
with the following extra keyword arguments.
-
version
a string specifying the version of this shared library, such as1.1.0
. On Linux and OS X, this is used to set the shared library version in the filename, such aslibfoo.so.1.1.0
andlibfoo.1.1.0.dylib
. If this is not specified,soversion
is used instead (see below). -
soversion
a string specifying the soversion of this shared library, such as0
. On Linux and Windows this is used to set the soversion (or equivalent) in the filename. For example, ifsoversion
is4
, a Windows DLL will be calledfoo-4.dll
and one of the aliases of the Linux shared library would belibfoo.so.4
. If this is not specified, the first part ofversion
is used instead. For example, ifversion
is3.6.0
andsoversion
is not defined, it is set to3
. -
vs_module_defs
a string pointing to a file that contains Visual Studio symbol export definitions.
buildtarget shared_module(module_name, list_of_sources, ...)
Builds a shared module with the given sources. Positional and keyword arguments are the same as for library
.
This is useful for building modules that will be dlopen()
ed and hence may contain undefined symbols that will be provided by the library that is loading it.
Added 0.37.0
buildtarget static_library(library_name, list_of_sources, ...)
Builds a static library with the given sources. Positional and keyword arguments are otherwise the same as for library
, but it has one argument the others don't have:
-
pic
, (Added 0.36.0) builds the library as positional independent code (so it can be linked into a shared library). This option has no effect on Windows and OS X since it doesn't make sense on Windows and PIC cannot be disabled on OS X.
void subdir(dir_name)
Enters the specified subdirectory and executes the meson.build
file in it. Once that is done, it returns and execution continues on the line following this subdir()
command. Variables defined in that meson.build
file are then available for use in later parts of the current build file and in all subsequent build files executed with subdir()
.
Note that this means that each meson.build
file in a source tree can and must only be executed once.
subproject_object subproject(subproject_name, ...)
Takes the project specified in the positional argument and brings that in the current build specification by returning a subproject object. Subprojects must always be placed inside the subprojects
directory at the top source directory. So for example a subproject called foo
must be located in ${MESON_SOURCE_ROOT}/subprojects/foo
. Supports the following keyword arguments:
-
version
keyword argument that works just like the one independency
. It specifies what version the subproject should be, as an example>=1.0.1
-
default_options
, (added 0.37.0) an array of default option values that override those set in the project'sdefault_options
invocation (likedefault_options
inproject
, they only have effect when Meson is run for the first time, and command line arguments override any default options in build files)
void test(name, executable, ...)
Defines an unit test. Takes two positional arguments, the first is the name of this test and the second is the executable to run. Keyword arguments are the following.
-
args
arguments to pass to the executable -
env
environment variables to set, such as['NAME1=value1', 'NAME2=value2']
, or anenvironment()
object which allows more sophisticated environment juggling -
is_parallel
when false, specifies that no other test must be running at the same time as this test -
should_fail
when true the test is considered passed if the executable returns a non-zero return value (i.e. reports an error) -
valgrind_args
if the test is run under Valgrind, pass these arguments to Valgrind (and not to the executable itself) -
timeout
the amount of seconds the test is allowed to run, a test that exceeds its time limit is always considered failed, defaults to 30 seconds -
workdir
absolute path that will be used as the working directory for the test
Defined tests can be run in a backend-agnostic way by calling mesontest
inside the build dir, or by using backend-specific commands, such as ninja test
or msbuild RUN_TESTS.vcxproj
.
ctarget vcs_tag(...)
This command detects revision control commit information at build time and places it in the specified output file. This file is guaranteed to be up to date on every build. Keywords are similar to custom_target
and all of them are mandatory.
-
input
file to modify (e.g.version.c.in
) -
output
file to write the results to (e.g.version.c
) -
fallback
version number to use when no revision control information is present, such as when building from a release tarball
Meson will read the contents of input
, replace the string @VCS_TAG@
with the detected revision number and write the result to output
. This method returns an opaque custom_target
object that you should put in your main program. If you desire more specific behavior than what this command provides, you should use custom_target
.
Meson has several different object types that have methods users can call. This section describes them.
The meson
object allows you to introspect various properties of the system. This object is always mapped in the meson
variable. It has the following methods.
-
get_compiler(language)
returns an object describing a compiler, takes one positional argument which is the language to use. It also accepts one keyword argument,native
which when set to true makes Meson return the compiler for the build machine (the "native" compiler) and when false it returns the host compiler (the "cross" compiler). Ifnative
is omitted, Meson returns the "cross" compiler if we're currently cross-compiling and the "native" compiler if we're not. -
backend()
(added 0.37.0) returns a string representing the current backend:ninja
,vs2010
,vs2015
, orxcode
. -
is_cross_build()
returnstrue
if the current build is a cross build andfalse
otherwise -
is_unity()
returnstrue
when doing a unity build andfalse
otherwise -
is_subproject()
returnstrue
if the current project is being built as a subproject of some other project andfalse
otherwise -
has_exe_wrapper()
returns true when doing a cross build if there is a wrapper command that can be used to execute cross built binaries (for example when cross compiling from Linux to Windows, one can usewine
as the wrapper) -
add_install_script(script_name, arg1, arg2, ...)
causes the script given as an argument to be run during the install step, this script will have the environment variablesMESON_SOURCE_ROOT
,MESON_BUILD_ROOT
,MESON_INSTALL_PREFIX
, andMESON_INSTALL_DESTDIR_PREFIX
set. All additional arguments are passed as parameters.MESON_INSTALL_PREFIX
has the value of theprefix
option passed to Meson, andMESON_INSTALL_DESTDIR_PREFIX
has both the value ofDESTDIR
andprefix
joined together. This is useful because both are absolute paths, and many path-joining functions such asos.path.join
in Python special-case absolute paths. -
add_postconf_script(script_name, arg1, arg2, ...)
will run the executable given as an argument after all project files have been generated. This script will have the environment variablesMESON_SOURCE_ROOT
andMESON_BUILD_ROOT
set. -
current_source_dir()
returns a string to the current source directory. Note: you do not need to use this function when passing files from the current source directory to a function since that is the default. Also, you can use thefiles()
function to refer to files in the current or any other source directory instead of constructing paths manually withmeson.current_source_dir()
. -
current_build_dir()
returns a string to the current build directory -
source_root()
returns a string with the absolute path to the source root directory. Note: you should use thefiles()
function to refer to files in the root source directory instead of constructing paths manually withmeson.source_root()
. -
build_root()
returns a string with the absolute path to the build root directory -
project_version()
returns the version string specified inproject
function call -
project_name()
returns the project name specified in theproject
function call -
version()
return a string with the version of Meson -
get_cross_property(propname, fallback_value)
returns the given property from a cross file, the optional second argument is returned if not cross compiling or the given property is not found -
install_dependency_manifest(output_name)
installs a manifest file containing a list of all subprojects, their versions and license files to the file name given as the argument
Provides information about the build machine — the machine that is doing the actual compilation. See Cross-compilation. It has the following methods:
-
cpu_family()
returns the CPU family name. Guaranteed to returnx86
for 32-bit userland on x86 CPUs,x86_64
for 64-bit userland on x86 CPUs,arm
for 32-bit userland on all ARM CPUs, etc. -
cpu()
returns a more specific CPU name, such asi686
,amd64
, etc. -
system()
returns the operating system name, such aswindows
(all versions of Windows),linux
(all Linux distros),darwin
(all versions of OS X), etc. -
endian()
returnsbig
on big-endian systems andlittle
on little-endian systems.
If you think the returned values for any of these are incorrect for your system or CPU, please file a bug report.
Provides information about the host machine — the machine on which the compiled binary will run. See Cross-compilation.
It has the same methods as build_machine
, but note that it simply returns the values defined in the cross-info file.
Provides information about the target machine — the machine on which the compiled binary's output will run. Hence, this object should only be used while cross-compiling a compiler. See Cross-compilation.
It has the same methods as build_machine
, but note that it simply returns the values defined in the cross-info file. If target_machine
values are not defined in the cross-info file, host_machine
values are returned instead.
A build target is either an executable, shared or static library.
-
extract_objects()
returns an opaque value representing the generated object files of arguments, usually used to take single object files and link them to unit tests or to compile some source files with custom flags. To use the object file(s) in another build target, use theobjects:
keyword argument. -
extract_all_objects()
is same as above but returns all object files generated by this target -
private_dir_include()
returns a opaque value that works likeinclude_directories
but points to the private directory of this target, usually only needed if an another target needs to access some generated internal headers of this target -
full_path()
returns a full path pointing to the result target file
This object is returned by meson.get_compiler(lang)
. It represents a compiler for a given language and allows you to query its properties. It has the following methods:
-
get_id()
returns a string identifying the compiler (e.g.'gcc'
) -
version()
returns the compiler's version number as a string -
find_library(lib_name, ...)
tries to find the library specified in the positional argument. The result object can be used just like the return value ofdependency
. If the keyword argumentrequired
is false, Meson will proceed even if the library is not found. By default the library is searched for in the system library directory (e.g. /usr/lib). This can be overridden with thedirs
keyword argument, which can be either a string or a list of strings. -
sizeof(typename, ...)
returns the size of the given type (e.g.'int'
) or -1 if the type is unknown, to add includes set them in theprefix
keyword argument, you can specify external dependencies to use withdependencies
keyword argument -
alignment(typename)
returns the alignment of the type specified in the positional argument, you can specify external dependencies to use withdependencies
keyword argument -
compiles(code)
returns true if the code fragment given in the positional argument compiles, you can specify external dependencies to use withdependencies
keyword argument,code
can be either a string containing source code or afile
object pointing to the source code -
links(code)
returns true if the code fragment given in the positional argument compiles and links, you can specify external dependencies to use withdependencies
keyword argument,code
can be either a string containing source code or afile
object pointing to the source code -
run(code)
attempts to compile and execute the given code fragment, returns a run result object, you can specify external dependencies to use withdependencies
keyword argument,code
can be either a string containing source code or afile
object pointing to the source code -
has_header
returns true if the specified header can be included, you can specify external dependencies to use withdependencies
keyword argument and extra code to put above the header test with theprefix
keyword. In order to look for headers in a specific directory you can useargs : '-I/extra/include/dir
, but this should only be used in exceptional cases for includes that can't be detected via pkg-config and passed viadependencies
. -
has_type(typename)
returns true if the specified token is a type, you can specify external dependencies to use withdependencies
keyword argument -
has_function(funcname)
returns true if the given function is provided by the standard library or a library passed in with theargs
keyword, you can specify external dependencies to use withdependencies
keyword argument -
has_member(typename, membername)
takes two arguments, type name and member name and returns true if the type has the specified member, you can specify external dependencies to use withdependencies
keyword argument -
has_members(typename, membername1, membername2, ...)
takes at least two arguments, type name and one or more member names, returns true if the type has all the specified members, you can specify external dependencies to use withdependencies
keyword argument -
has_header_symbol(headername, symbolname)
allows one to detect whether a particular symbol (function, variable, #define, type definition, etc) is declared in the specified header, you can specify external dependencies to use withdependencies
keyword argument -
has_argument(argument_name)
returns true if the compiler accepts the specified command line argument, that is, can compile code without erroring out or printing a warning about an unknown flag, you can specify external dependencies to use withdependencies
keyword argument -
has_multi_arguments(arg1, arg2, arg3, ...)
is the same ashas_argument
but takes multiple arguments and uses them all in a single compiler invocation, available since 0.37.0 -
first_supported_argument(list_of_strings)
, given a list of strings, returns the first argument that passes thehas_argument
test above or an empty array if none pass -
symbols_have_underscore_prefix()
returnstrue
if the C symbol mangling is one underscore (_
) prefixed to the symbol, available since 0.37.0 -
compute_int(expr, ...')
computes the value of the given expression (as an example1 + 2
). When cross compiling this is evaluated with an iterative algorithm, you can specify keyword argumentslow
(defaults to -1024),high
(defaults to 1024) andguess
to specify max and min values for the search and the value to try first.
The following keyword arguments can be used:
-
name
the name to use for printing a message about the compiler check. Supported by the methodscompiles()
,links()
, andrun()
. If this kwarg is not passed to those methods, no message will be printed about the check. -
prefix
can be used to add #includes and other things that are required for the symbol to be declared. System definitions should be passed via compiler args (eg:_GNU_SOURCE
is often required for some symbols to be exposed on Linux, and it should be passed viaargs
keyword argument, see below). Supported by the methodssizeof
,has_type
,has_function
,has_member
,has_members
,has_header_symbol
. -
include_directories
specifies extra directories for header searches. (added 0.38.0) -
args
can be used to pass a list of compiler arguments that are required to find the header or symbol. For example, you might need to pass the include path-Isome/path/to/header
if a header is not in the default include path. In versions newer than 0.38.0 you should use theinclude_directories
keyword described above. You may also want to pass a library name-lfoo
forhas_function
to check for a function. Supported by all methods exceptget_id
,version
, andfind_library
.
Note that if you have a single prefix with all your dependencies, you might find it easier to append to the environment variables C_INCLUDE_PATH
with gcc/clang and INCLUDE
with msvc to expand the default include path, and LIBRARY_PATH
with gcc/clang and LIB
with msvc to expand the default library search path.
However, with GCC, these variables will be ignored when cross-compiling. In that case you need to use a specs file. See: http://www.mingw.org/wiki/SpecsFileHOWTO
This object encapsulates the result of trying to compile and run a sample piece of code with compiler.run()
. It has the following methods:
-
compiled()
if true, the compilation succeeded, if false it did not and the other methods return unspecified data -
returncode()
the return code of executing the compiled binary -
stdout()
the standard out produced when the binary was run -
stderr()
the standard error produced when the binary was run
This object is returned by configuration_data
and encapsulates configuration values to be used for generating configuration files. A more in-depth description can be found in the the configuration wiki page It has three methods:
-
set(varname, value)
, sets a variable to a given value -
set10(varname, boolean_value)
is the same as above but the value is eithertrue
orfalse
and will be written as 1 or 0, respectively -
set_quoted(varname, value)
is same asset
but quotes the value in double quotes ("
) -
has(varname)
, returnstrue
if the specified variable is set -
get(varname, default_value)
returns the value ofvarname
, if the value has not been set returnsdefault_value
if it is defined (added 0.38.0) and errors out if not
They all take the description
keyword that will be written in the result file. The replacement assumes a file with C syntax. If your generated file is source code in some other language, you probably don't want to add a description field because it most likely will cause a syntax error.
This object is returned by dependency
and contains an external dependency with the following methods:
-
found()
which returns whether the dependency was found -
type_name()
which returns a string describing the type of the dependency, the most common values areinternal
for deps created withdeclare_dependencies
andpkgconfig
for system dependencies obtained with Pkg-config. -
version()
is the version number as a string, for example1.2.8
-
get_pkgconfig_variable(varname)
(Added 0.36.0) will get the pkg-config variable specified, or, if invoked on a non pkg-config dependency, error out
This object is returned by find_program
and contains an external (i.e. not built as part of this project) program and has the following methods:
-
found()
which returns whether the executable was found -
path()
which returns an array pointing to the executable (this is an array as opposed to a string because the program might be['python', 'foo.py']
, for example)
This object is returned by environment()
and stores detailed information about how environment variables should be set during tests. It should be passed as the env
keyword argument to tests. It has the following methods.
-
set(varname, value)
sets environment variable in the first argument to the value in the second argument, e.g.env.set('FOO', 'BAR') sets envvar
FOOto value
BAR` -
append(varname, value)
appends the given value to the old value of the environment variable, e.g.env.append'('FOO', 'BAR', separator : ';')
producesBOB;BAR
ifFOO
had the valueBOB
and plainBAR
if the value was not defined. If the separator is not specified explicitly, the default path separator for the host operating system will be used, i.e. ';' for Windows and ':' for UNIX/POSIX systems. -
prepend(varname, value)
is the same asappend
except that it writes to the beginning of the variable
This object is returned by find_library
and contains an external (i.e. not built as part of this project) library. This object has only one method, found
, which returns whether the library was found.
This object is returned by generator
and contains a generator that is used to transform files from one type to another by an executable (e.g. idl
files into source code and headers).
-
process(list_of_files)
takes a list of files, causes them to be processed and returns an object containing the result which can then, for example, be passed into a build target definition. The keyword argumentextra_args
, if specified, will be used to replace an entry@EXTRA_ARGS@
in the argument list.
This object is returned by subproject
and is an opaque object representing it.
-
get_variable(name)
fetches the specified variable from inside the subproject. This is useful to, for instance, get a declared dependency from the subproject.
All strings have the following methods. Strings are immutable, all operations return their results as a new string.
-
strip()
removes whitespace at the beginning and end of the string -
format()
formats text, see the Syntax manual for usage info -
to_upper()
creates an upper case version of the string -
to_lower()
creates a lower case version of the string -
underscorify()
creates a string where every non-alphabetical non-number character is replaced with_
-
split(split_character)
splits the string at the specified character (or whitespace if not set) and returns the parts in an array -
startswith(string)
returns true if string starts with the string specified as the argument -
endswith(string)
returns true if string ends with the string specified as the argument -
contains(string)
returns true if string contains the string specified as the argument -
to_int
returns the string converted to an integer (error if string is not a number) -
join(list_of_strings)
is the opposite of split, for example'.'.join(['a', 'b', 'c']
yields'a.b.c'
-
version_compare(comparison_string)
does semantic version comparison, ifx = '1.2.3'
thenx.version_compare('>1.0.0')
returnstrue
Numbers support these methods:
-
is_even()
returns true if the number is even -
is_odd()
returns true if the number is odd
A boolean object has two simple methods:
-
to_string()
returns the string'true'
if the boolean is true or'false'
otherwise. You can also pass it two strings as positional arguments to specify what to return for true/false. For instance,bool.to_string('yes', 'no')
will returnyes
if the boolean is true andno
if it is false. -
to_int()
as above, but returns either1
or0
The following methods are defined for all arrays:
-
length()
, the size of the array -
contains(item)
, returnstrue
if the array contains the object given as argument,false
otherwise -
get(index, fallback)
, returns the object at the given index, negative indices count from the back of the array, indexing out of bounds returns thefallback
value (added 0.38.0) or, if it is not specified, causes a fatal error
You can also iterate over arrays with the foreach
statement.
All documentation is now on the main web site.
This page should be at this address.