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| -rw-r--r-- | docs/markdown/Dependencies.md | 63 |
1 files changed, 46 insertions, 17 deletions
diff --git a/docs/markdown/Dependencies.md b/docs/markdown/Dependencies.md index 3aa82b4..8e780d6 100644 --- a/docs/markdown/Dependencies.md +++ b/docs/markdown/Dependencies.md @@ -45,7 +45,52 @@ non-found dependencies. The dependency detector works with all libraries that provide a `pkg-config` file. Unfortunately several packages don't provide -pkg-config files. Meson has autodetection support for some of these. +pkg-config files. Meson has autodetection support for some of these, +and they are described later on this page. + +# Declaring your own + +You can declare your own dependency objects that can be used +interchangeably with dependency objects obtained from the system. The +syntax is straightforward: + +```meson +my_inc = include_directories(...) +my_lib = static_library(...) +my_dep = declare_dependency(link_with : my_lib, + include_directories : my_inc) +``` + +This declares a dependency that adds the given include directories and +static library to any target you use it in. + +# Building dependencies as subprojects + +Many platforms do not provide a system package manager. On these +systems dependencies must be compiled from source. Meson's subprojects +make it simple to use system dependencies when they are available and +to build dependencies manually when they are not. + +To make this work, the dependency must have Meson build definitions +and it must declare its own dependency like this: + + foo_dep = declare_dependency(...) + +Then any project that wants to use it can write out the following +declaration in their main `meson.build` file. + + foo_dep = dependency('foo', fallback : ['foo', 'foo_dep']) + +What this declaration means is that first Meson tries to look up the +dependency from the system (such as by using pkg-config). If it is not +available, then it builds subproject named `foo` and from that +extracts a variable `foo_dep`. That means that the return value of +this function is either an external or an internal dependency +object. Since they can be used interchangeably, the rest of the build +definitions do not need to care which one it is. Meson will take care +of all the work behind the scenes to make this work. + +# Dependencies with custom lookup functionality ## Boost @@ -162,19 +207,3 @@ automatically: ```meson libwmf_dep = dependency('libwmf', version : '>=0.2.8') ``` - -## Declaring your own - -You can declare your own dependency objects that can be used -interchangeably with dependency objects obtained from the system. The -syntax is straightforward: - -```meson -my_inc = include_directories(...) -my_lib = static_library(...) -my_dep = declare_dependency(link_with : my_lib, - include_directories : my_inc) -``` - -This declares a dependency that adds the given include directories and -static library to any target you use it in. |