How to catch runtime error?

[laszlo]

Consider the following program

$repeat=1000;

for ($i=0; $i<$repeat;$i++) {println();}
if ($@) {print "$@"; die;}
print "done";

sub println {
my $s = shift;
#if (! defined($s)) {$s = "";}
print "$s\n";
if ($@) {print "$@"; die;}
}

If I run it from command mode with -W parameter I get

"Use of unitialized value in concatenation (.) or string in a.txt line
9.

error message for every execution of the sub

However if I use in IIS (WIN2000 Service pack 4; Active State Perl
5.8 806) inside a larger program as part of an

eval({$program})
if ($@) {report the error; die}

statement, the program does not report any error just dies and the
browser (IE 6.0) shows an irrelevant "the page cannot be displayed"
error message.

If I lower thwe value of $repeat to 100 or less, the program finishes
w/o any error message , also if I remove the # comment before the

#if (! defined($s)) {$s = "";}

line, the program runs w/o any problem for reasonable sizes.

In my website environment the program runs, but no error message is
given

http://lzkiss.netfirms.com/cgi-bin/igperl/igp.pl?dir=test&name=test

Any help appreciated

laszlo

 

[Tad McClellan]

If I run it from command mode with -W parameter I get

"Use of unitialized value in concatenation (.) or string in a.txt line
9.

error message for every execution of the sub

That is not an error message.

That is a warning message.

However if I use in IIS (WIN2000 Service pack 4; Active State Perl
5.8 806) inside a larger program as part of an

eval({$program})
if ($@) {report the error; die}

statement, the program does not report any error just dies and the
browser (IE 6.0) shows an irrelevant "the page cannot be displayed"
error message.

Does it put the message in the web server's log?

Any help appreciated

Warnings are not trapped the same way as errors, see

perldoc -f eval

for how to use $SIG{__WARN__}.

 

[Anno Siegel]

That is not an error message.

That is a warning message.




Does it put the message in the web server's log?




Warnings are not trapped the same way as errors, see

perldoc -f eval

for how to use $SIG{__WARN__}.

As an alternative, one can make the warning in question fatal and
catch it in eval. In this case:

eval { use warnings FATAL => qw( uninitialized); <whatever> }

That is sometimes easier than fiddling with a handler.

Anno

 

[laszlo]

As an alternative, one can make the warning in question fatal and
catch it in eval. In this case:

eval { use warnings FATAL => qw( uninitialized); <whatever> }

That is sometimes easier than fiddling with a handler.

Anno

Thanks for both info. I put

use warnings FATAL => qw(all);

statement in front of my text to be avaluated, and the interpreter
faithfully listed all the warnings.