Detecting (null) in Objective-C

Question

I want to detect whether passing a NSString to NSLog will return (null). I've tried if (string == @"") {do something}" and if (string == @"(null)") {do something}" but neither seem to work. Any advice would be greatly appreciated!

Answer 1

if (string == nil) {
   do_something;
}

Answer 2

Your "NSString" is actually a pointer to an NSString (i.e. an NSString *). A null pointer in C is simply a pointer with the value 0; in C, 0 is false, so the following is simple and idiomatic:

NSString *str = ...;
if (str) {
    /// str is not null
}

(p.s.: Your comparisons with @"" and @"(null)" are comparing the addresses of the NSString pointers, not the values; to compare NSStrings, look at -isEqualToString:.)