No need to use before_exec() to call setpgid()

.travis.yml

@@ -8,10 +8,10 @@ env:
 matrix:
   include:
     - os: linux
-      rust: nightly
+      rust: stable
       env: TARGET=x86_64-unknown-linux-gnu
     - os: osx
-      rust: nightly
+      rust: stable
       env: TARGET=x86_64-apple-darwin
 
 script:

README.md

@@ -22,6 +22,8 @@ Example use cases:
 * By default, uses `.gitignore` to determine which files to ignore notifications for
 * Support for watching files with a specific extension
 * Support for filtering/ignoring events based on glob patterns
+* Launches child processes in a new process group
+* Sets `$WATCHEXEC_UPDATED_PATH` in the environment of the child process to the first file that triggered a change
 * Optionally clears screen between executions
 * Optionally restarts the command with every modification (good for servers)
 * Does not require a language runtime

appveyor.yml

@@ -3,7 +3,7 @@ environment:
     PROJECT_NAME: watchexec
   matrix:
     - TARGET: x86_64-pc-windows-gnu
-      CHANNEL: nightly
+      CHANNEL: stable
 
 # Install Rust and Cargo
 # (Based on from https://github.com/rust-lang/libc/blob/master/appveyor.yml)

src/main.rs

@@ -1,5 +1,3 @@
-#![feature(process_exec)]
-
 #[macro_use]
 extern crate clap;
 extern crate env_logger;

src/runner.rs

@@ -1,4 +1,3 @@
-use libc;
 use std::process::{Child, Command};
 
 pub struct Runner {
@@ -33,6 +32,8 @@ impl Runner {
 
     #[cfg(target_family = "unix")]
     fn kill(child: &mut Child) {
+        use libc;
+
         extern {
             fn killpg(pgrp: libc::pid_t, sig: libc::c_int) -> libc::c_int;
         }
@@ -56,7 +57,7 @@ impl Runner {
 
     #[cfg(target_family = "unix")]
     fn invoke(&self, cmd: &str, updated_paths: Vec<&str>) -> Option<Child> {
-        use std::os::unix::process::CommandExt;
+        use libc;
 
         let mut command = Command::new("sh");
         command.arg("-c").arg(cmd);
@@ -65,10 +66,17 @@ impl Runner {
             command.env("WATCHEXEC_UPDATED_PATH", updated_paths[0]);
         }
 
-        command
-            .before_exec(|| unsafe { libc::setpgid(0, 0); Ok(()) })
+        let child = command
             .spawn()
-            .ok()
+            .ok();
+
+        if let &Some(ref c) = &child {
+            unsafe {
+                libc::setpgid(c.id() as i32, c.id() as i32);
+            }
+        }
+
+        child
     }
 
     pub fn run_command(&mut self, cmd: &str, updated_paths: Vec<&str>) {
@@ -98,6 +106,8 @@ impl Runner {
 
     #[cfg(target_family = "unix")]
     fn wait(child: &mut Child) {
+        use libc;
+
         unsafe {
             let pid = child.id() as i32;
             let status: Box<i32> = Box::new(0);