Re: quoted execution not working

perl is trying to execute another program, but there is not enought memory to run it. How can I validate that this is the case?

Well... here's a few thoughts: first change how you are doing your forks:

:
: handwaving
:
my $pid=fork();
if ( $pid == 0 } {
   : child process goes here
} elsif { $pid > 0 ) {
   : parent process
    wait();  # Wait for the child to exit
} else {
    # WOAH! We should never get here! 
    die "fork returned $pid";
}
[download]

Within your child process instead of using backticks you couold do the following

: child
   open(PIPE,"some_command 2>&1 |") 
       or die $!;
   my @output=<PIPD>;
   close PIPE;
   print @output;
[download]

This way if you fail to fork off the grandchild you will see a diagnostic from die.

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Re^2: quoted execution not working by dave_the_m (Monsignor) on Jul 27, 2004 at 23:44 UTC
`my $pid=fork(); if ( $pid == 0 } { : child process goes here } elsif { $pid > 0 ) { : parent process wait(); # Wait for the child to exit } else { # WOAH! We should never get here! die "fork returned $pid"; }` [download] There are two things wrong with that. If the fork fails, $pid is undef, but will still compare true to 0. Second, if it fails, the error is in $!, not $pid. So you actually want: `my $pid=fork(); if (not defined $pid) { die "fork failed: $!\n"; } elsif ( $pid == 0 } { : child process goes here } else { : parent process wait(); # Wait for the child to exit }` [download] Dave.	[reply] [d/l] [select]
Re^3: quoted execution not working by blue_cowdawg (Monsignor) on Jul 28, 2004 at 00:10 UTC
If the fork fails, $pid is undef, but will still compare true to 0. Second, if it fails, the error is in $!, not $pid. Good catch! You are correct. My bad. Instead of `die "fork returned $pid";` [download] I should have invoked `die $!;` [download] as I have in code that I have written in the past where I have done forking. Too much C-code lately the if-tree is a C-ism. As in `pid = fork(); switch (pid){ -1: perror("Fork failed"); exit(-1); 0: /* Child / break; default: / parent */ break; }` [download] anyway, good catch. All all this code is off the top of my head.	[reply] [d/l] [select]