catching "Use of uninitialized value" warnings

[badarisj]

folks,

now and then we see
Use of uninitialized value in xxx
warning messages while running a perl program.

is there a way to catch such warning messages that perl throws and
display
the stack that is leading to the warning message?

thanks,
-badari

 

[Oobi Van Doobi]

folks,

now and then we see
Use of uninitialized value in xxx
warning messages while running a perl program.

is there a way to catch such warning messages that perl throws and
display
the stack that is leading to the warning message?

thanks,
-badari

umm, a good thing to do would be to check if variables you use are
inizialised. you can do so with for example:
if ( defined($variable) )
{
...code here...
}

 

[vparseval]

now and then we see
Use of uninitialized value in xxx
warning messages while running a perl program.

is there a way to catch such warning messages that perl throws and
display
the stack that is leading to the warning message?

For development purposes you can install a SIGWARN handler that will
print a stacktrace when the warning message conforms to certain
criteria:

#!/usr/bin/perl

use warnings;

$SIG{__WARN__} = sub {
if ($_[0] =~ /^Use of uninitialized value/) {
require Carp;
Carp::cluck();
} else {
warn @_;
}
};

sub foo {
print undef;
}

sub bla {
foo();
}

bla(42);
__END__
at cluck.pl line 6
main::__ANON__('Use of uninitialized value in print at
cluck.pl line 13.\x{a}') called at cluck.pl line 13
main::foo() called at confess.pl line 17
main::bla(42) called at confess.pl line 20

Cheers,
Tassilo

 

[badarisj]

hi tassilo,

thanks a lot. i didn't realize that all messages that the perl
interpreter
shows can be trapped using __WARN__ or __DIE__ sighandlers.
works well for what i want.

-badari

now and then we see
Use of uninitialized value in xxx
warning messages while running a perl program.

is there a way to catch such warning messages that perl throws and
display
the stack that is leading to the warning message?

For development purposes you can install a SIGWARN handler that will
print a stacktrace when the warning message conforms to certain
criteria:

#!/usr/bin/perl

use warnings;

$SIG{__WARN__} = sub {
if ($_[0] =~ /^Use of uninitialized value/) {
require Carp;
Carp::cluck();
} else {
warn @_;
}
};

sub foo {
print undef;
}

sub bla {
foo();
}

bla(42);
__END__
at cluck.pl line 6
main::__ANON__('Use of uninitialized value in print at
cluck.pl line 13.\x{a}') called at cluck.pl line 13
main::foo() called at confess.pl line 17
main::bla(42) called at confess.pl line 20

Cheers,
Tassilo