Exit with a number

Scarborough has asked for the wisdom of the Perl Monks concerning the following question:

I have read that using exit 1; is an exceptable way of exiting from a program however when I've done something like this

#in first_prog.pl
#do something wrong 
exit 1;
[download]

and then in a second program

 
$result = system "perl first_prog.pl"
print $result;
#I get 256
[download]

I've read somewhere that exit cannot be relide upon but why?

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Re: Exit with a number by gellyfish (Monsignor) on Aug 03, 2004 at 14:21 UTC
That 256 is correct - you need to `print $result >>8` to get rid of the first eight bits of the number which are put there by the OS /J\	[reply] [d/l]
Re: Exit with a number by sweetblood (Prior) on Aug 03, 2004 at 14:27 UTC
from perldoc -f system The return value is the exit status of the program as returned by the "wait" call. To get the actual exit value divide by 256. Sweetblood	[reply]
Re: Exit with a number by mifflin (Curate) on Aug 03, 2004 at 15:48 UTC
System's return value has a lot of information in it. `$exit_value = $result >> 8; $signal_num = $result & 127; $dumped_core = $result & 128;` [download]	[reply] [d/l]
Re: Exit with a number by Your Mother (Archbishop) on Aug 03, 2004 at 23:57 UTC
I think it's a holdover from shell stuff. "0" is really the non-error, non-problem exit code. All the integers indicate something that needs attention (and the messages are different by OS/environment). `perldoc -f exit` for more.	[reply] [d/l]