From 2c8ff1d47bab77295920cec7b0cb2d40257d2167 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <superjoe30@gmail.com>
Date: Fri, 8 Sep 2017 01:23:48 -0400
Subject: [PATCH] std.ChildProcess.spawn: handle 0 from waitpid correctly

---
 std/os/child_process.zig | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/std/os/child_process.zig b/std/os/child_process.zig
index 1ab1a9fa35..3f3ddf03bf 100644
--- a/std/os/child_process.zig
+++ b/std/os/child_process.zig
@@ -340,6 +340,9 @@ extern fn sigchld_handler(_: i32) {
     while (true) {
         var status: i32 = undefined;
         const pid_result = posix.waitpid(-1, &status, posix.WNOHANG);
+        if (pid_result == 0) {
+            return;
+        }
         const err = posix.getErrno(pid_result);
         if (err > 0) {
             if (err == posix.ECHILD) {