perldoc -f system says:
The return value is the exit status of the program as returned by the "wait" call. To get the actual exit value, shift right by eight.

...

Return value of -1 indicates a failure to start the program or an error of the wait(2) system call (inspect $! for the reason).

So if nmake returns a failure it should return a positive integer, not -1, which would only returned if nmake wasn't found or similar.

I would code this like that: (untested)

my $pid = open (NMAKE, '-|', "nmake .... 2>&1");
if (!defined $pid) {
   warn "Couldn't start nmake";
}
while (<NMAKE>) {
    print STDERR $_;
    print STDOUT $_;
}
close (NMAKE);
my $status = $?;
if ($status) {
   # ...
}

[download]

In reply to Re^3: Get Return Value from Unix by mscharrer
in thread Get Return Value from Unix by Noame

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.