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You call waitpid after you've reaped the process, causing causing an error ($? = -1;, error message in $!).

You gotta check $? after the successful call to waitpid.

use POSIX qw( WNOHANG ); my $pid = system(1,'perl -e"sleep(4); exit(5);"'); while (1) { my $wait = waitpid($pid, WNOHANG); die $! if $wait < 0; last if $wait > 0; } print "Command completed with exit code $?.\n";

I presume you actually do something else in the loop? If not, there's no reason to use WHOHANG.

my $pid = system(1,'perl -e"sleep(4); exit(5);"'); waitpid($pid, 0); die $! if $? < 0; print "Command completed with exit code $?.\n";

In reply to Re^3: Getting a return code from waitpid in Windows by ikegami
in thread Getting a return code from waitpid in Windows by Anonymous Monk

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