Building a framework in PHP

[Dark_Greg]

I am currently developing a framework in PHP4, underwhich all of my web applications will run.

My question is, is there a) a way to "over-ride" existing php functions, and b) a way to trap functions as they are run ...

for example

if a function "somefunc" is run, it will automatically call a function in the framework class, which will determine if the function is allowed, log errors and what not, and then run "somefunc"...

sorry if this is poorly explained....I hope someone gets what I am on about...