Question

In PHP, is there any way that I can ignore functions that are undefined instead of throwing a fatal error that is visible in the browser?—i.e., Fatal error: Call to undefined function

I know that there is the practice of wrapping all custom functions in a conditional as below, but is there a programmatic way to get this effect?

if (function_exists('my_function')) { 

   // use my_function() here;

}

Answer 1

No. Fatal errors are fatal. Even if you were to write your own error handler or use the @ error suppression operator, E_FATAL errors will still cause the script to halt execution.

The only way to handle this is to use function_exists() (and possibly is_callable() for good measure) as in your example above.

It’s always a better idea to code defensively around a potential (probable?) error than it is to just let the error happen and deal with it later anyway.

EDIT – php7 has changed this behavior, and undefined functions/methods are catchable exceptions.