Question

Yes, the problem is with a library I’m using, and no, I cannot modify it. I need a workaround.

Basically, I’m dealing with a badly written Perl library, that exits with ‘die’ when a certain error condition is encountered reading a file. I call this routine from a program which is looping through thousands of files, a handful of which are bad. Bad files happen; I just want my routine to log an error and move on.

IF I COULD modify the library, I would simply change the

die 'error'; 

to a

print 'error';return; 

, but I cannot. Is there any way I can couch the routine so that the bad files won’t crash the entire process?

FOLLOWUP QUESTION: Using an ‘eval’ to couch the crash-prone call works nicely, but how do I set up handling for catch-able errors within that framework? To describe:

I have a subroutine that calls the library-which-crashes-sometimes many times. Rather than couch each call within this subroutine with an eval{}, I just allow it to die, and use an eval{} on the level that calls my subroutine:

my $status=eval{function($param);}; unless($status){print $@; next;}; # print error and go to next file if function() fails 

However, there are error conditions that I can and do catch in function(). What is the most proper/elegant way to design the error-catching in the subroutine and the calling routine so that I get the correct behavior for both caught and uncaught errors?

Answer 1

You could wrap it in an eval. See:

perldoc -f eval 

For instance, you could write:

# warn if routine calls die eval { routine_might_die }; warn $@ if $@; 

This will turn the fatal error into a warning, which is more or less what you suggested. If die is called, $@ contains the string passed to it.