Unable to print after while loop in perl - perl

Question

BEGIN {
use FindBin;
$scriptsDir = $FindBin::RealBin;
}
sub print_log {
($log, $msg) = ($_[0], $_[1]);
print $log $msg;
}
$opt_rh_gsr = "path_to_file";
open(FO, "$opt_rh_gsr") || die "-F-: Can not open file \n";
while(<FO>) {
if(/vdd_nets/) {
$vdd_net = 1;
$vdd_string = "VDD_NETS \{ \n";
}
if(/gnd_nets/) {
$gnd_net = 1;
}
if(($gnd_net == 1)) {
chomp();
$new_line = $_;
#split_new_line = split(":", $new_line);
}
if(($gnd_net == 1) && /\}/) {
$gnd_net = 0;
$gnd_string .= "\} \n";
exit;
}
if($vdd_net) {
if(/^\s*\S+\s+\S+\s+{/) {
$paren++;
}
if (0 != $paren && /^\s*(\w+)\s*$/) {
$vdd_nets{$1} = $parenvolt;
next;
}
if(/^\s*}\s*$/ || /^\s+$/) {
if (0 == $paren) {
$vdd_net = 0; next;
}
else {
$paren--; next;
}
}
chomp();
if(/\s*\}\s*$/ && ($vdd_net == 1)){
s/\'//g;
$vdd_net = 0;
#_ = split(":");
$vdd_string .= "$_[0] $_[1] \n";
$vdd_string .= "\} \n";
next;
}
if($gnd_net) {
if(/^\s*\}\s+$/ || /^\s+$/) {
$gnd_net = 0;
next;
}
#chomp();
if(/\s*\}\s*$/ && ($gnd_net == 1)){
s/\'//g;
$gnd_net = 0;
}
#_ = split();
$GNDNET = $_[0];
if ($_[0] =~ /^\w+$/) {
$groundnets{$_[0]} = 1;
}
}
}
}
print " done reading \n";
close(FO);
print "closed file \n";
The above is not printing the last 2 print statement (before and after the close of file handle). I tried print STDOUT, that didn't work. I also tried to flush, that didn't work either.
The script is exiting after executing, so it is not stuck in a infinite loop anywhere. I tries using perl5.6 and 5.8, but both of them have the same problem.

Answer 1

To exit a loop, you should use the keyword last instead of exit (which exits the whole program). This if:
if(($gnd_net == 1) && /\}/) {
$gnd_net = 0;
$gnd_string .= "\} \n";
print "exiting loop $gnd_string \n";
exit;
}
Should thus be:
if(($gnd_net == 1) && /\}/) {
$gnd_net = 0;
$gnd_string .= "\} \n";
print "exiting loop $gnd_string \n";
last;
}
(unless you actually wanted to exit the program, in which case the print should rather have been print "exiting program...")
A few tips:
Always add use strict and use warnings at the beginning of your scripts. It will catch many mistakes and save you a lot of time.
Use 3-operand open to open files (ie, open FILEHANDLE,MODE,EXPR instead of open FILEHANDLE,EXPR), and lexical filehandles (ie, $FO instead of FO). Your open should thus have been: open my $FO, '<', $opt_rh_gsr instead of open(FO, "$opt_rh_gsr").
Adding || die "-F-: Can not open file \n" after open is a good idea, but 1) you should do or die instead of || die (in this specific case it doesn't matter, but with or rather than ||, you can omit the parenthesis around open's arguments), and 2) you should add the name of the file you were trying to open (in that case, you'd print die "-F-: Can not open file '$opt_rh_gsr'). 3) add $! to the die to have the error message (die "-F-: Can not open file '$opt_rh_gsr': $!). And 4), as suggested by TLP, don't add a newline at the end of a die string.
sub print_log { ($log, $msg) = ($_[0], $_[1]); ... could have been sub print_log { ($log, $msg) = #_;; it's a bit more idiomatic and concise.
Indent properly your code. It's possible that indentation was lost in the copy-paste, but, if it's not the case, then you should indent better your code. This will save you a lot of time when writing/reading your code, and will save other people even more time when they'll read your code. Most IDEs have indentation features that can help you indent the code.