errorlevel in perl - perl

Question

I need to terminate the perl script according to the return code from the previous step.
something like
IF ERRORLEVEL 1 goto ERROR
in batch processing.
i have
$PROG = `spu_comp 2>&1 $a 1 1`;
i need if this step gives error, program should terminate.
thanks in advance for your inputs.

Answer 1

Immediately after the line where you assign to $PROG, add this line:
($? >> 8) and die "spu_comp exited with non-zero return value";

Answer 2

$ perl -le'`sh -c "exit 0"`;($?>>8) and die "exited with non-zero: ", ($?>>8)'
$ perl -le'`sh -c "exit 1"`;($?>>8) and die "exited with non-zero: ", ($?>>8)'
exited with non-zero: 1 at -e line 1.

Answer 3

It appears that ERRORLEVEL is not a true exit code to perl.
i have the same issue. A bat file of
#Echo OFF
echo setting error level 1
EXIT /B 1
With a perl file of
#!/usr/bin/perl
$command = `C:\foo.bat`;
print "Error Level: " .$? ."\n";
print "Command: " . $command . "\n";
Yields output of
Error Level: 0
Command:
A perl file of
#!/usr/bin/perl
my $command = `dir`;#try both dir and dri to test real exit codes against batch exit codes
print "Error Level: " .$? ."\n";
print "Command: " . $command . "\n";
will yield
C:\>back.pl
'dri' is not recognized as an internal or external command,
operable program or batch file.
Error Level: 256
Command:
C:\>back.pl
Error Level: 0
Command: Volume in drive C has no label.
Volume Serial Number is 8068-BE74
Directory of C:\
12/13/2010 11:02 AM 7 8
06/02/2010 01:13 PM 0 AUTOEXEC.BAT
06/04/2010 01:00 PM <DIR> AutoSGN
12/13/2010 12:03 PM 111 back.pl
06/02/2010 01:13 PM 0 CONFIG.SYS
06/03/2010 07:37 PM <DIR> Documents and Settings
12/13/2010 12:01 PM 46 foo.bat
06/04/2010 03:17 PM <DIR> HorizonTemp
06/02/2010 02:41 PM <DIR> Intel
06/04/2010 02:19 PM <DIR> league
06/04/2010 12:31 PM <DIR> Perl
12/10/2010 03:28 PM <DIR> Program Files
12/08/2010 04:13 PM <DIR> Quarantine
12/13/2010 08:14 AM <DIR> WINDOWS
5 File(s) 164 bytes
9 Dir(s) 18,949,783,552 bytes free
C:\>

Answer 4

You can get the correct return code from $PROG by adding the following line.
my $ret = $?/256 #/
or a cleaner way
my $ret = $? >> 8;
Then compare the $ret with the possible values you can retrieve
if ($ret == 0)
{
# Do something if finished successfully
}
elsif($ret == 1)
{
error();
}
else
{
# Return something else that was nor 0 nor 1
}

Answer 5

Further to #husker's answer, it's worth noting $? only works for codes of 255 or less. Windows error codes typically exceed this. The IPC::System::Simple module, however, provides methods like capture() that can correctly retrieve codes > 255.
e.g.
use Test::More;
use IPC::System::Simple qw(capture $EXITVAL EXIT_ANY);
my $modeTest = capture(EXIT_ANY, "some command that sets error code 5020");
is( $EXITVAL , 5020, "Expect error code 5020" );