Re: Perl Forking : perform some action until child process dies

The issue you are encountering is that waitpid ($pid,0) is a blocking call. This means that the conditional on your until loop doesn't finish executing until your child has actually returned. You can perform a non-blocking call on systems that support it using:

use POSIX ":sys_wait_h";
#...
do {
    $kid = waitpid(-1, WNOHANG);
} while $kid > 0;
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where the above is copied from waitpid. Note that not all systems support non-blocking calls to waitpid. See also perlipc.

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Re^2: Perl Forking : perform some action until child process dies by robrt (Novice) on Sep 03, 2010 at 04:48 UTC
Many thanx... this worked But I used "while $kid = = 0; " instead.. which means.. while the child process is still running.. keep calculating the bandwidth in the do { }	[reply]