os: fix WNOHANG Waitmsg

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4962042

diff --git a/src/pkg/os/exec_unix.go b/src/pkg/os/exec_unix.go
index 8a4b2e1b8060913a30b00abd7633ff0d5d92d453..41e77230ad5a466a6c5da08a03bba3a3db7d881e 100644 (file)
--- a/src/pkg/os/exec_unix.go
+++ b/src/pkg/os/exec_unix.go
@@ -38,7 +38,8 @@ func (p *Process) Wait(options int) (w *Waitmsg, err Error) {
        if e != 0 {
                return nil, NewSyscallError("wait", e)
        }
-       if options&WSTOPPED == 0 {
+       // With WNOHANG pid is 0 if child has not exited.
+       if pid1 != 0 && options&WSTOPPED == 0 {
                p.done = true
        }
        w = new(Waitmsg)