lazylink
Convert extern fn to libdl call procedural macro.
```rust
use lazylink::lazylink;
/// comment!
[lazylink]
[link(name = "z")]
extern "C" {
/// zlib version
#[linkname = "zlibVersion"]
fn zlibversion() -> *const std::os::raw::c_char;
}
[lazylink(fullname = "libc.so.6")]
mod libc {
/// comment!
extern "C" {
pub(crate) fn puts(v: *const std::os::raw::c_char);
}
}
fn main() {
let ver = unsafe {
zlib_version()
};
unsafe {
libc::puts(ver);
}
}
```
into
```rust
![feature(prelude_import)]
[prelude_import]
use std::prelude::v1::*;
[macro_use]
extern crate std;
use lazylink::lazylink;
struct LazyLinkbfde0578a8e5d844<'a> {
/// comment!
/// zlib version
zlibversion:
lazylink::libloading::Symbol<'a, unsafe extern "C" fn() -> *const std::os::raw::cchar>,
phantom: std::marker::PhantomData &'a ()>,
}
impl<'a> _LazyLinkbfde0578a8e5d844<'a> {
unsafe fn new(
lib: &'a lazylink::libloading::Library,
) -> Result {
Ok(
Self { # [doc = " comment!"] # [doc = " zlib version"] zlibversion : lib . get (b"zlibVersion\x00") ? , _pha
ntom : std :: marker :: PhantomData , },
)
}
fn get() -> &'static _LazyLinkbfde0578a8e5d844<'static> {
static mut LIB: Option = None;
static mut FNS: Option<__LazyLinkbfde0578a8e5d844<'static>> = None;
static ONCE: std::sync::Once = std::sync::Once::new();
ONCE.callonce(|| unsafe {
LIB = Some(
lazylink::libloading::Library::new(lazylink::libloading::libraryfilename("z"))
.unwrap(),
);
FNS = Some(LazyLinkbfde0578a8e5d844::new(LIB.asref().unwrap()).unwrap());
});
unsafe { FNS.asref().unwrap() }
}
}
/// comment!
/// zlib version
unsafe fn zlibversion() -> *const std::os::raw::cchar {
(LazyLinkbfde0578a8e5d844::get().zlibversion)()
}
mod libc {
struct _LazyLink79e825dc6d38824d<'a> {
/// comment!
puts: lazylink::libloading::Symbol<'a, unsafe extern "C" fn(*const std::os::raw::cchar)>,
_phantom: std::marker::PhantomData &'a ()>,
}
impl<'a> _LazyLink79e825dc6d38824d<'a> {
unsafe fn new(
lib: &'a lazylink::libloading::Library,
) -> Result {
Ok(
Self { # [doc = " comment!"] puts : lib . get (b"puts\x00") ? , phantom : std :: marker :: PhantomData ,
},
)
}
fn get() -> &'static _LazyLink79e825dc6d38824d<'static> {
static mut LIB: Option = None;
static mut FNS: Option<__LazyLink79e825dc6d38824d<'static>> = None;
const ONCE: std::sync::Once = std::sync::Once::new();
ONCE.callonce(|| unsafe {
LIB = Some(lazylink::libloading::Library::new("libc.so.6").unwrap());
FNS = Some(LazyLink79e825dc6d38824d::new(LIB.asref().unwrap()).unwrap());
});
unsafe { FNS.asref().unwrap() }
}
}
/// comment!
pub(crate) unsafe fn puts(v: *const std::os::raw::cchar) {
(_LazyLink79e825dc6d38824d::get().puts)(v)
}
}
fn main() {
let ver = unsafe { zlibversion() };
unsafe {
libc::puts(ver);
}
}
```
License
Licensed under either of
- Apache License, Version 2.0
(LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license
(LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.