Re: system() Creating Different Results than Commandline Operation.

By the way, what's with ">/dev/null" on Windows? That should be ">nul".

It's actually simpler to make it portable:

sub system_no_output {
    my $mode = shift;

    open(my $chld_in, '<&', *STDIN) or die($!);
    my $chld_out = '>&STDOUT';
    my $chld_err = '>&STDERR';

    open($chld_out=undef, '>', devnull()) or die($!)   if $mode & 1;
    open($chld_err=undef, '>', devnull()) or die($!)   if $mode & 2;

    my $pid = open3($chld_in, $chld_out, $chld_err, @_)
        or die($!);

    return waitpid($pid, 0);
}
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Comment on Re: system() Creating Different Results than Commandline Operation. Select or Download Code

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Re^2: system() Creating Different Results than Commandline Operation. by kazeits (Initiate) on Apr 06, 2009 at 18:02 UTC
due to major changes to gcov over versions it needs to be opened to see what version is installed. the code makes a call to: `if (system_no_output(3, $gcov_tool, "--help") == -1)` [download] using your solution to rewrite system_no_output seems to hang waiting for gcov to return. I don't understand why.	[reply] [d/l]
Re^3: system() Creating Different Results than Commandline Operation. by ikegami (Patriarch) on Apr 06, 2009 at 18:12 UTC
`-1` is not a valid value for `$?`, so it's a bug to expect `system_no_output` to return `-1`. If you want `-1` when `system` fails and `$?` otherwise, you want: `# Your version $result = system(@_);` [download] `# My version my $pid = open3($chld_in, $chld_out, $chld_err, @_) or return -1;` [download] your solution to rewrite system_no_output seems to hang waiting for gcov to return `system` waits for the child to return, so I did the same.	[reply] [d/l] [select]