catch() - catch an evaluation error
mixed catch( mixed expr );
Evaluate <expr>. If there is no error, 0 is returned. If there is a standard error, a string (with a leading '*') will be returned. The function throw() can also be used to immediately return any value, except 0. catch() is not really a function call, but a directive to the compiler. The catch() is somewhat costly, and should not be used just anywhere. Rather, use it at places where an error would destroy consistency.
error(3), throw(3), error_handler(4)