open2 successfully created the child (fork), so it returned the child's PID. But the child process was unable to execute the desired command (exec), so it died, setting the child's error code to something non-zero.

To check if the child is still running, use
kill(0, $pid) or
waitpid($pid, WNOHANG) (less portable?) or
eof($out) (good indicator, but not always correct).

waitpid returns a number which includes the child's error code. See $? for details.

You should be calling waitpid when using open2/open3 even if you don't care about the error code, or else you'll leave zombie processes behind.

In reply to Re: Is it possible to detect "no file" error in open2 ? by ikegami
in thread Is it possible to detect "no file" error in open2 ? by bdimych

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