Add ppoll()

Author: Susurrus

CHANGELOG.md

@@ -39,6 +39,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
   ([#508](https://github.com/nix-rust/nix/pull/508))
 - Fixed the style of many bitflags and use `libc` in more places.
   ([#503](https://github.com/nix-rust/nix/pull/503))
+- Added `ppoll` in `::nix::poll`
+  ([#520](https://github.com/nix-rust/nix/pull/520))
 
 ### Changed
 - `epoll_ctl` now could accept None as argument `event`

src/poll.rs

@@ -1,3 +1,6 @@
+use sys::time::TimeSpec;
+use sys::signal::SigSet;
+
 use libc;
 use {Errno, Result};
 
@@ -47,3 +50,14 @@ pub fn poll(fds: &mut [PollFd], timeout: libc::c_int) -> Result<libc::c_int> {
 
     Errno::result(res)
 }
+
+pub fn ppoll(fds: &mut [PollFd], timeout: TimeSpec, sigmask: SigSet) -> Result<libc::c_int> {
+
+    let res = unsafe {
+        libc::ppoll(fds.as_mut_ptr() as *mut libc::pollfd,
+                    fds.len() as libc::nfds_t,
+                    timeout.as_ref(),
+                    sigmask.as_ref())
+    };
+    Errno::result(res)
+}