# Pkgconfig module This module is a simple generator for [pkg-config](https://pkg-config.freedesktop.org/) files. ## Usage ```meson pkg = import('pkgconfig') bar_dep = dependency('bar') lib = library('foo', dependencies : [bar]) pkg.generate(lib) ``` ### pkg.generate() The generated file's properties are specified with the following keyword arguments. - `description` a string describing the library, used to set the `Description:` field - `extra_cflags` a list of extra compiler flags to be added to the `Cflags` field after the header search path - `filebase` the base name to use for the pkg-config file; as an example, the value of `libfoo` would produce a pkg-config file called `libfoo.pc` - `install_dir` the directory to install to, defaults to the value of option `libdir` followed by `/pkgconfig` - `libraries` a list of built libraries (usually results of shared_library) that the user needs to link against. Arbitrary strings can also be provided and they will be added into the `Libs` field. Since 0.45.0 dependencies of built libraries will be automatically added, see the [Implicit dependencies](#implicit-dependencies) section below for the exact rules. Since 0.58.0 custom_target() objects are supported as long as they are linkable (has known extension such as `.a`, `.so`, etc). - `libraries_private` list of built libraries or strings to put in the `Libs.private` field. Since 0.45.0 dependencies of built libraries will be automatically added, see the [Implicit dependencies](#implicit-dependencies) section below for the exact rules. Since 0.58.0 custom_target() objects are supported as long as they are linkable (has known extension such as `.a`, `.so`, etc). - `name` the name of this library, used to set the `Name:` field - `subdirs` which subdirs of `include` should be added to the header search path, for example if you install headers into `${PREFIX}/include/foobar-1`, the correct value for this argument would be `foobar-1` - `requires` list of strings, pkgconfig-dependencies or libraries that `pkgconfig.generate()` was used on to put in the `Requires` field - `requires_private` same as `requires` but for `Requires.private` field field - `url` a string with a url for the library - `variables` a list of strings with custom variables to add to the generated file. The strings must be in the form `name=value` and may reference other pkgconfig variables, e.g. `datadir=${prefix}/share`. The names `prefix`, `libdir` and `includedir` are reserved and may not be used. *Since 0.56.0* it can also be a dictionary but ordering of Meson dictionaries are not guaranteed, which could cause issues when some variables reference other variables. Spaces in values are escaped with `\`, this is required in the case the value is a path that and is used in `cflags` or `libs` arguments. *Since 0.59.0* if escaping is not desired (e.g. space separate list of values) `unescaped_variables` keyword argument should be used instead. *Since 0.62.0* builtin directory variables that are referenced are automatically created by default. - `uninstalled_variables` used instead of the `variables` keyword argument, when generating the uninstalled pkg-config file. Since *0.54.0* Spaces in values are escaped with `\`, this is required in the case the value is a path that and is used in `cflags` or `libs` arguments. *Since 0.59.0* if escaping is not desired (e.g. space separate list of values) `unescaped_uninstalled_variables` keyword argument should be used instead. - `version` a string describing the version of this library, used to set the `Version:` field. (*since 0.46.0*) Defaults to the project version if unspecified. - `d_module_versions` a list of module version flags used when compiling D sources referred to by this pkg-config file - `dataonly` field. (*since 0.54.0*) this is used for architecture-independent pkg-config files in projects which also have architecture-dependent outputs. - `conflicts` (*since 0.36.0, incorrectly issued a warning prior to 0.54.0*) list of strings to be put in the `Conflicts` field. Since 0.46 a `StaticLibrary` or `SharedLibrary` object can optionally be passed as first positional argument. If one is provided a default value will be provided for all required fields of the pc file: - `install_dir` is set to `pkgconfig` folder in the same location than the provided library. - `description` is set to the project's name followed by the library's name. - `name` is set to the library's name. Since 0.54.0 uninstalled pkg-config files are generated as well. They are located in `/meson-uninstalled/`. It is sometimes useful to build projects against libraries built by Meson without having to install them into a prefix. In order to do so, just set `PKG_CONFIG_PATH=/meson-uninstalled` before building your application. That will cause pkg-config to prefer those `-uninstalled.pc` files and find libraries and headers from the Meson builddir. This is an experimental feature provided on a best-effort basis, it might not work in all use-cases. ### Implicit dependencies The exact rules followed to find dependencies that are implicitly added into the pkg-config file have evolved over time. Here are the rules as of Meson *0.49.0*, previous versions might have slightly different behaviour. - Not found libraries or dependencies are ignored. - Libraries and dependencies are private by default (i.e. added into `Requires.private:` or `Libs.private:`) unless they are explicitly added in `libraries` or `requires` keyword arguments, or is the main library (first positional argument). - Libraries and dependencies will be de-duplicated, if they are added in both public and private (e.g `Requires:` and `Requires.private:`) it will be removed from the private list. - Shared libraries (i.e. `shared_library()` and **NOT** `library()`) add only `-lfoo` into `Libs:` or `Libs.private:` but their dependencies are not pulled. This is because dependencies are only needed for static link. - Other libraries (i.e. `static_library()` or `library()`) add `-lfoo` into `Libs:` or `Libs.private:` and recursively add their dependencies into `Libs.private:` or `Requires.private:`. - Dependencies provided by pkg-config are added into `Requires:` or `Requires.private:`. If a version was specified when declaring that dependency it will be written into the generated file too. - The threads dependency (i.e. `dependency('threads')`) adds `-pthread` into `Libs:` or `Libs.private:`. - Internal dependencies (i.e. `declare_dependency(compiler_args : '-DFOO', link_args : '-Wl,something', link_with : foo)`) add `compiler_args` into `Cflags:` if public, `link_args` and `link_with` into `Libs:` if public or `Libs.private:` if private. - Other dependency types add their compiler arguments into `Cflags:` if public, and linker arguments into `Libs:` if public or `Libs.private:` if private. - Once a pkg-config file is generated for a library using `pkg.generate(mylib)`, any subsequent call to `pkg.generate()` where mylib appears, will generate a `Requires:` or `Requires.private` instead of a `Libs:` or `Libs.private:`.