给rust链接windows下的资源或者c/c++的.o文件

本文是用编译脚本（build.rs）的方式链接windows下的资源

1、原理

编译脚本的用法可以看下面这个官方的链接

http://doc.crates.io/build-script.html

下面这个是官方的例子，是用gcc将.c文件生成.o，然后ar打包，最后cargo build链接

// build.rs

use std::process::Command;
use std::env;
use std::path::Path;

fn main() {
let out_dir = env::var("OUT_DIR").unwrap();

// note that there are a number of downsides to this approach, the comments
// below detail how to improve the portability of these commands.
Command::new("gcc").args(&["src/hello.c", "-c", "-fPIC", "-o"])
.arg(&format!("{}/hello.o", out_dir))
.status().unwrap();
Command::new("ar").args(&["crus", "libhello.a", "hello.o"])
.current_dir(&Path::new(&out_dir))
.status().unwrap();

println!("cargo:rustc-link-search=native={}", out_dir);
println!("cargo:rustc-link-lib=static=hello");
}

2、编译链接windows下的资源

这里需要用到mingw里的windres.exe和ar.exe

下面是toml文件，需要把build=”build.rs”加进去：

[package]

name = "examples"
version = "0.0.1"
authors = [...]
build="build.rs"

下面是build.rs里的代码，与toml文件放在同一个目录即可：

// build.rs

use std::process::Command;
use std::env;
use std::path::Path;

fn main() {
let out_dir = env::var("OUT_DIR").ok().expect("can't find out_dir");

// note that there are a number of downsides to this approach, the comments
// below detail how to improve the portability of these commands.
Command::new("windres").args(&["src/hello.rc",  "-o"])
.arg(&format!("{}/hello2.o", out_dir))
.status().unwrap();
Command::new("ar").args(&["crus", "libhello.a", "hello2.o"])
.current_dir(&Path::new(&out_dir))
.status().unwrap();

println!("cargo:rustc-link-search=native={}", out_dir);
println!("cargo:rustc-link-lib=static=hello");
}

build.rs流程：

用windres.exe把src/hello.rc文件编译成hello2.o

用ar工具把hello2.o打包成libhello.a

最后两个println!是让cargo去out_dir用-l static=hello的方式链接libhello.a

设置好了toml，写好build.rs运行：cargo build即可