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Bug 633

Summary: Incorrect use of the kill($pid, 0) idiom.
Product: SDL Reporter: Michael Stone <michael>
Component: audioAssignee: Ryan C. Gordon <icculus>
Status: RESOLVED FIXED QA Contact: Sam Lantinga <slouken>
Severity: normal    
Priority: P2    
Version: HG 2.0   
Hardware: x86   
OS: Linux   
URL: http://dev.laptop.org/ticket/8307

Description Michael Stone 2008-09-25 19:27:29 UTC 
To determine whether a pid is occupied with the kill(pid, 0) idiom, you have to test 

#include <signal.h>
#include <errno.h>
kill(pid, 0) < 0 && errno == ESRCH

not just

#include <signal.h>
kill(pid, 0) < 0

otherwise you get incorrect results when pid is running as a different user (causing kill(pid, 0) to return -1 + EPERM).

src/audio/alsa/SDL_alsa_audio.c is certainly affected by this bug in both 1.2.13 and 1.3-trunk. It probably occurs in other places as well.
Comment 1 Sam Lantinga 2009-02-16 21:18:19 UTC 
Thanks, this is fixed in revision 4433.