iPhone SDK Objective-C __DATE __（编译日期）无法转换为NSDate

//NSString *compileDate = [NSString stringWithFormat:@"%s", __DATE__];
NSString *compileDate = [NSString stringWithUTF8String:__DATE__];

NSDateFormatter *df = [[[NSDateFormatter alloc] init] autorelease];

[df setDateFormat:@"MMM d yyyy"];   
//[df setDateFormat:@"MMM dd yyyy"];    

NSDate *aDate = [df dateFromString:compileDate];  
//NSString *compileDate = [NSString stringWithF