docs: Explain how to use a Vala project's VAPI files with find_library() [skip ci]

The Vala compiler object's find_libary() method needs the 'dir' keyword to
add a project's local vapi dir to the VAPI search path.

See https://github.com/mesonbuild/meson/issues/4702
pull/4787/head
Alistair Thomas 6 years ago committed by Jussi Pakkanen
parent bbcf80d734
commit 2f72d4db09
  1. 58
      docs/markdown/Vala.md

@ -18,7 +18,7 @@ dependencies = [
sources = files('app.vala')
executable('app_name', sources, dependencies : dependencies)
executable('app_name', sources, dependencies: dependencies)
```
You must always specify the `glib-2.0` and `gobject-2.0` libraries as
@ -53,7 +53,7 @@ This first example is a simple addition to the `meson.build` file because:
* the library has a `pkg-config` file, `gtk+-3.0.pc`
* the VAPI is distributed with Vala and so installed with the Vala compiler
* the VAPI is installed in Vala's standard search path
* the VAPI has the same name as the `pkg-config` file, `gtk+-3.0.vapi`
* the VAPI, `gtk+-3.0.vapi`, has the same name as the `pkg-config` file
Everything works seamlessly in the background and only a single extra line is
needed:
@ -69,7 +69,7 @@ dependencies = [
sources = files('app.vala')
executable('app_name', sources, dependencies : dependencies)
executable('app_name', sources, dependencies: dependencies)
```
GTK+ is the graphical toolkit used by GNOME, elementary OS and other desktop
@ -104,7 +104,7 @@ dependencies = [
sources = files('app.vala')
executable('app_name', sources, dependencies : dependencies)
executable('app_name', sources, dependencies: dependencies)
```
Using `[GtkTemplate]` also requires the GTK+ user interface definition files to
@ -128,7 +128,7 @@ sources += import( 'gnome' ).compile_resources(
source_dir: 'src/resources',
)
executable('app_name', sources, dependencies : dependencies)
executable('app_name', sources, dependencies: dependencies)
```
@ -146,10 +146,11 @@ the VAPI search path. In Meson this is done with the `add_project_arguments()`
function:
```meson
project('vala app', 'c', 'vala')
project('vala app', 'vala', 'c')
vapi_dir = join_paths(meson.current_source_dir(), 'vapi')
add_project_arguments(['--vapidir', join_paths(meson.current_source_dir(), 'vapi')],
language: 'vala')
add_project_arguments(['--vapidir', vapi_dir], language: 'vala')
dependencies = [
dependency('glib-2.0'),
@ -159,7 +160,7 @@ dependencies = [
sources = files('app.vala')
executable('app_name', sources, dependencies : dependencies)
executable('app_name', sources, dependencies: dependencies)
```
If the VAPI is for an external library then make sure that the VAPI name
@ -179,7 +180,7 @@ with the `vala-extra-vapis` repository.
### Libraries without pkg-config files
A library that does not have a corresponding pkg-config file may mean
`dependency()` is unsuitable for finding the C and Vala interface files. In this
case it is necessary to use `find_library()`.
case it is necessary to use the `find_library()` method of the compiler object.
The first example uses Vala's POSIX binding. There is no pkg-config file because
POSIX includes the standard C library on Unix systems. All that is needed is the
@ -198,7 +199,7 @@ dependencies = [
sources = files('app.vala')
executable('app_name', sources, dependencies : dependencies)
executable('app_name', sources, dependencies: dependencies)
```
The next example shows how to link with a C library where no additional VAPI is
@ -217,8 +218,39 @@ dependencies = [
sources = files('app.vala')
executable('app_name', sources, dependencies : dependencies)
executable('app_name', sources, dependencies: dependencies)
```
The `required: false` means the build will continue when using another C library
that does not separate the maths library. See [Add math library (-lm)
portably](howtox.md#add-math-library-lm-portably).
The final example shows how to use a library that does not have a pkg-config
file and the VAPI is in the `vapi` directory of your project source files:
```meson
project('vala app', 'vala', 'c')
vapi_dir = join_paths(meson.current_source_dir(), 'vapi')
add_project_arguments(['--vapidir', vapi_dir], language: 'vala')
dependencies = [
dependency('glib-2.0'),
dependency('gobject-2.0'),
meson.get_compiler('c').find_library('foo'),
meson.get_compiler('vala').find_library('foo', dir: vapi_dir),
]
sources = files('app.vala')
executable('app_name', sources, dependencies: dependencies)
```
The `find_library()` method of the C compiler object will try to find the C
header files and the library to link with.
The `find_library()` method of the Vala compiler object needs to have the `dir`
keyword added to include the project VAPI directory. This is not added
automatically by `add_project_arguments()`.
## Building libraries
@ -260,7 +292,7 @@ Meson can generate a GIR as part of the build. For a Vala library the
`vala_gir` option has to be set for the `library`:
```meson
foo_lib = library('foo', 'foo.vala',
foo_lib = shared_library('foo', 'foo.vala',
vala_gir: 'Foo-1.0.gir',
dependencies: [glib_dep, gobject_dep],
install: true,

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