{{works with|clang-602.0.53}}

The de facto Objective-C "Hello, World!" program is most commonly illustrated as the following, using the NSLog() function:


#import <Foundation/Foundation.h>

int main() {
    @autoreleasepool {
        NSLog(@"Hello, World!");
    }
}


However the purpose of the NSLog() function is to print a message to standard error prefixed with a timestamp, which does not meet the most common criteria of a "Hello, World!" program of displaying only the requested message to standard output.

The following code prints the message to standard output without a timestamp using exclusively Objective-C messages:


#import <Foundation/Foundation.h>

int main() {
    @autoreleasepool {
        NSFileHandle *standardOutput = [NSFileHandle fileHandleWithStandardOutput];
        NSString *message = @"Hello, World!\n";
        [standardOutput writeData:[message dataUsingEncoding:NSUTF8StringEncoding]];
    }
}


Objective-C also supports functions contained within the C standard library. However, Objective-C's NSString objects must be converted into a UTF-8 string in order to be supported by the C language's I/O functions.


#import <Foundation/Foundation.h>

int main() {
    @autoreleasepool {
        NSString *message = @"Hello, World!\n";
        printf("%s", message.UTF8String);
    }
}