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
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)