Your subject line got me really confused. :-)
rrs
On Sat, 24 Dec 2005, Mayank Jain wrote:
> #include <unistd.h>
> #include <sys/types.h>
> #include <stdio.h>
> #include <sys/wait.h>
>
> int main()
> {
> pid_t child = 0;
> int status = 0;
> printf("forking!\n");
>
> child = fork();
> if(child == 0)
> {
> printf("Inside child\n");
> sleep(2);
> printf("Finishing if\n");
> }
> else
> {
> printf("Inside Parent\n");
> while(1)
> {
> printf("Calling waitpid\n");
> waitpid(child, &status, 0);
> if(WIFEXITED(status))
> {
> printf("Child exited\n");
> break;
> }
> }
> printf("Finishing else\n");
> }
> }
>
>
> The above code works perfectly, the parent waits for the child to die
> & then exits itself.
>
> [EMAIL PROTECTED]:~/junk# ./child
> forking!
> Inside child
> Inside Parent
> Calling waitpid
> Finishing if
> Child exited
> Finishing else
> [EMAIL PROTECTED]:~/junk#
>
>
> However, how do i make this wait by the parent a non-blocking wait?
> This is because while checking for "has the child died", parent is
> blocked by waitpid & hence cannot do other processing.
>
> I've tried using WNOHANG in waitpid as waitpid(child, &status,
> WNOHANG) & this is the output i get
>
> [EMAIL PROTECTED]:~/junk# ./child
> forking!
> Inside child
> Inside Parent
> Calling waitpid
> Child exited
> Finishing else
> [EMAIL PROTECTED]:~/junk#
> [EMAIL PROTECTED]:~/junk# Finishing if
> [EMAIL PROTECTED]:~/junk#
>
> Notice that parent exited before child died.
>
> Am i using WNOHANG in a wrong way? or in a wrong place? What can be
> other strategies i can use? I dont want to use threads as they'll be
> an overkill (all i want to do is keep parent in non-blocking state,
> while looping for child's alive status).
>
>
> --
> regards,
> makuchaku
> ---
> http://makuchaku.info
> When you speak out with the courage of your convictions, people listen!
> -- Valmik Thapar, Wildlife Conservationist.
>
>
--
Ritesh Raj Sarraf
RESEARCHUT -- http://www.researchut.com
"Stealing logic from one person is plagiarism, stealing from many is research."
"Necessity is the mother of invention."
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