Error wrapping in an OO module

[Fang]

Hi all,

I am writing an OO module for my own needs (and as a learning experience as well), and I am trying to gather all the error messages possibly emitted by other modules (DBI, mainly). So far, I have laid down the following course of action:

1. any potentially error-emitting method (eg. DBI->connect()) should be called with or die and enclosed in an eval block
2. if an error ends up in $@, set a private variable to a meaningful string and exit returning a value representing failure, most probably undef

The private variable is simply called _error, accessed by an error() method that simply returns the string and resets _error to the empty string.

So far, this works fine under the environment I am using (mod_perl), with one little issue: if the constructor method encounters an error and returns undef, I can't use it like this for obvious reason:

my $obj = MyModule->new() or die $obj->error();

DBI uses a global variable for a similar purpose I believe, any caveat I should be aware of before trying that myself?

To sum it up, I am looking for advices concerning any better method I couldn't think of to achieve the same thing, whether it is a commonly used and proven solution, or an existing module (I have searched for "error", "wrapper", and many variations thereof but didn't quite find a fitting tool).

Thanks in advance for any advice you will provide.

[tlm]

There are many approaches, some more suitable than others depending on the application. The topic has been discussed often, including a couple of times recently:

1. Thinking about module error handling
2. Error handling - how much/where/how?

the lowliest monk

[Fang]

Thanks for the links. I feel slightly ashamed not to have thought about searching for "handling" and its variations... I'll go read those nodes for sure.

[mattk]

You might be interested in reading about exception objects, too.