How to propagate errors from the deepest depths of my code to the browser?

[sneakyimp]

how does one propagate errors in class functions, etc. back up so that there is some output (or error logging) visible to the user?

i've seen code that had a custom data structure called a 'message_stack' but i'm wondering more about the basic theory and practice so that i can get my head around it. can anyone recommend either a strategy or some resources?

[Weedpacket]

I've used an extension called xdebug, which augments standard error messages with a stack trage.

[sneakyimp]

thanks for the reply!

i was hoping more for some heuristic advice...e.g., 'define a global array or object and write function so-and-so'. also, i am looking for something that isn't just for debugging, but also sending messages to the user like "couldn't create your page, one with that name already exists". i could implement all kinds of checks at every level of my code, but i have this intuitive feeling that some kind of message stack would be a more efficient way to do it.