in reply to Re: Effect of redirecting output to /dev/null on $? value
in thread Effect of redirecting output to /dev/null on $? value

`exec my_executable_that_seg_faults > /dev/null`;

exec at the start of a command is one of the few things that are treated specially in Perl_do_exec3(), see Re^2: Improve pipe open? (redirect hook). It seems to disable the default optimization and forces the use of the default shell.

There is a way to stay mentally sane on Unix/POSIX systems for I/O-redirection. Don't use system; instead, fork and exec manually:

# (untested) my $pid=fork(); my @cmd_and_args=('my_executable_that_seg_faults'); # maybe push @cmd_and_args,qw( some arguments for the program ); defined($pid) or die "Can't fork: $!"; if ($pid) { # parent process waitpid $pid; #<-- sets $? } else { # child process open STDOUT,'>','/dev/null' or die "Can't redirect STDOUT: $!"; exec { $cmd_and_args[0] } @cmd_and_args; die "exec failed: $!"; }

Note that ONLY indirect object notation on exec prevents all attempts of perl to be smart. See The problem of "the" default shell.


Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)