# sys

**Repository Path**: heiwuqi/sys

## Basic Information

- **Project Name**: sys
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-09-23
- **Last Updated**: 2024-09-07

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# sys

Autogenerated __FFI__ definitions for various __GNOME__ libraries.

## Building

This repository contains the "sys" crates – FFI definitions intended for 
use in the actual bindings (e.g. [gtk](https://github.com/gtk-rs/gtk)).

Each crate expects the development files of the respective library
to be installed on the system.

## Library versions

The installed library version is detected via `pkg-config` in the build
script, which controls conditional compilation so only the functions
availiable in that library version are visible.

For instance, if the `gdk-sys` crate's build script detects `libgdk3`
version `3.12`, it sets a number of `cfg` directives
`gdk_3_4`, `gdk_3_6`, ..., up to`gdk_3_12`.
Correspondingly, the definitions of functions introduced
in version `x.y` carry `#[cfg(gdk_x_y)]` attributes.
(The build script actually contains a complete list of the versions
it knows, `3.4` doesn't have any special meaning, it's just the first
in that list in that crate).
The build script passes that set of directives on to its dependencies, so
a depenendent crate's build script will see
```
env::var("DEP_GDK_CFG").unwrap() == "gdk_3_4 gdk_3_6 gdk_3_8 gdk_3_10 gdk_3_12"
```

## Generating

```shell
> make
```

will build the [generator](https://github.com/gtk-rs/gir) in `gir` and
generate the crates using specifications from `conf` and
[GIR definitions](https://github.com/gtk-rs/gir-files) from `gir-files`.

Currently `gir-files` is populated from the
[gnome-staging ppa](https://launchpad.net/~gnome3-team/+archive/ubuntu/gnome3-staging).
Using a single set of GIR definitions for all platforms and versions
is considered good enough at this point.