* system() return different value under 2.4.23 and 2.6.0-test11
@ 2003-12-04 5:01 fengxj
2003-12-04 10:21 ` Raj
0 siblings, 1 reply; 2+ messages in thread
From: fengxj @ 2003-12-04 5:01 UTC (permalink / raw)
To: linux-kernel
Hi, everyone
I just found a simple program:
-----------------------------
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
int main(void)
{
int ret;
signal(SIGCHLD, SIG_IGN);
ret = system("/bin/date 1>/dev/null");
printf("%d\n", ret);
return 0;
}
----------------------------
runs under 2.4.23 with ret = 0,
but under 2.6.0-test11, ret = -1.
Why?
And when i remove
signal(...)
it returns the same value 0.
I use Slackware 9.1 with GCC 3.2.3 and libc 2.3.2
Regards.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: system() return different value under 2.4.23 and 2.6.0-test11
2003-12-04 5:01 system() return different value under 2.4.23 and 2.6.0-test11 fengxj
@ 2003-12-04 10:21 ` Raj
0 siblings, 0 replies; 2+ messages in thread
From: Raj @ 2003-12-04 10:21 UTC (permalink / raw)
To: fengxj; +Cc: linux-kernel
fengxj wrote:
>-----------------------------
>#include <stdio.h>
>#include <stdlib.h>
>#include <signal.h>
>
>int main(void)
>{
> int ret;
>
> signal(SIGCHLD, SIG_IGN);
>
> ret = system("/bin/date 1>/dev/null");
> printf("%d\n", ret);
>
> return 0;
>}
>----------------------------
>
>runs under 2.4.23 with ret = 0,
>but under 2.6.0-test11, ret = -1.
>
>Why?
>
>And when i remove
> signal(...)
>it returns the same value 0.
>
>
It's happening because of the return values of wait4(). wait4() is
returning -1 in test11 whene SIGCHLD is SIG_IGN'ed.
/Raj
^ permalink raw reply [flat|nested] 2+ messages in thread
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