.DT undefinedp $MUDNAME$ driver help undefinedp .SH Name .SI 5 undefinedp() - determine whether or not a given variable is undefined .EI .SH Synopsis .SI 5 int undefinedp( mixed arg ); .EI .SH Description .SP 5 5 Return 1 if `arg' is undefined. `arg' will be undefined in the following cases: .EP .SO 5 2 70 * it is a variable set equal to the return value of a call_other to a non-existent method (e.g. arg = call_other(obj, "???")). * it is a variable set equal to the return value of an access of an element in a mapping that doesn't exist (e.g. arg = map[not_there]). * it has not yet been initialized. * it points to a destructed object. * it is a function (formal) parameter that corresponds to a missing actual argument. .EO .SH See also .SI 5 stringp(), pointerp(), objectp(), intp(), bufferp(), floatp(), functionp(), errorp(), mappingp(), typeof() .EI