Here’s some sample output — it looks much nicer in monospace. Notice that the class name and message name are treated as separate strings, so a long class name won’t obliterate a long message name. Works with blocks and C-functions too.

19:24:18.099 -[MyApplctnAp.. application:didFinishLa..]@28 App initializing…
19:24:18.212 -[UserLibrary getDeviceArtistsAndSongs]@118 querying user library
19:24:20.179 -[MyApplctnViewController activate]@93 actually activating…
19:24:20.180 cFoo @86 printing from C function
19:25:03.031 -[ScrollerController addMagazine:]@85 addMagazine Tyler, The Creator
19:25:03.234 -[ScrollerController pageTurnedFrom:to:]@201 0 -> 0
19:27:39.703 __+[GUtil asyncImageFrom..]_block_invoke_1@59 restarting async image load
19:29:57.541 -[MusicPage assembleAlbumView:]@121 image loaded

Enjoy!

///// ====== MyApplctn.h ======

#define DEBUG
#import “LogUtils.h”

///// ====== LogUtils.h ======
#import

// ALog always displays output regardless of the DEBUG setting
#define ALog(fmt, …) [LogUtils logString:[NSString stringWithFormat:fmt, ##__VA_ARGS__] fromMethod:[NSString stringWithUTF8String:__PRETTY_FUNCTION__] atLine:__LINE__];

// DLog is almost a drop-in replacement for NSLog
// DLog();
// DLog(@”here”);
// DLog(@”value: %d”, x);
// Unfortunately this doesn’t work DLog(aStringVariable); you have to do this instead DLog(@”%@”, aStringVariable);
#ifdef DEBUG
# define DLog(fmt, …) ALog(fmt, ##__VA_ARGS__)
#else
# define DLog(…)
#endif

@interface LogUtils : NSObject

+ (void)logString:(NSString *)str fromMethod:(NSString *)method atLine:(int)line;

+ (NSString *)forceString:(NSString *)str toLength:(int)chars;

@end

//// ====== LogUtils.m ======

#import “LogUtils.h”

@implementation LogUtils

static NSDateFormatter *dateFormatter;

+ (void)logString:(NSString *)str fromMethod:(NSString *)method atLine:(int)line {

if(dateFormatter == nil) {
dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"HH:mm:ss.SSS"];
}
NSString *time = [dateFormatter stringFromDate:[NSDate date]];

int METHOD_LENGTH = 42;
NSRange openRange = [method rangeOfString:@"["];
NSRange closeRange = [method rangeOfString:@"]“];

if(openRange.location == NSNotFound || closeRange.location == NSNotFound) {
method = [LogUtils forceString:method toLength:METHOD_LENGTH];
} else {
// looks like it’s an Objective-C method
// get fancy and abridge both the class and the message separately

NSString *prefix = [method substringToIndex:openRange.location+1];
NSString *meat = [method substringWithRange:NSMakeRange(openRange.location+1, closeRange.location - (openRange.location+1))];
NSString *suffix = [method substringFromIndex:closeRange.location];

float classToMessageRatio = .5;
int N = METHOD_LENGTH – prefix.length – suffix.length;
NSString *dots = @”..”;

NSRange spaceRange = [meat rangeOfString:@" "];
NSString *class = [meat substringToIndex:spaceRange.location];
NSString *message = [meat substringFromIndex:spaceRange.location];

if(meat.length <= N) {
while(class.length + message.length N; n–) {
float curRatio = (float)classLength / messageLength;
if(curRatio < classToMessageRatio) {
messageLength–;
} else {
classLength–;
}
}

if(classLength != class.length) {
int k = classLength – dots.length;
class = [[class substringToIndex:k] stringByAppendingString:dots];
}

if(messageLength != message.length) {
int k = messageLength – dots.length;
message = [[message substringToIndex:k] stringByAppendingString:dots];
}
}

method = [NSString stringWithFormat:@"%@%@%@%@", prefix, class, message, suffix];
}

NSString *lineString = [LogUtils forceString:[NSString stringWithFormat:@"%d", line] toLength:4];

NSString *output = [NSString stringWithFormat:@"%@ %@@%@ %@", time, method, lineString, str];
printf(”%s\n”, [output cStringUsingEncoding:NSUTF8StringEncoding]);
}

+ (NSString *)forceString:(NSString *)str toLength:(int)chars {
if(str.length <= chars) {
while(str.length < chars)
str = [str stringByAppendingString:@" "];
return str;
}

NSString *dots = @”…”;

if(str.length <= dots.length)
return [dots substringToIndex:str.length];

return [[str substringToIndex:chars - dots.length] stringByAppendingString:dots];
}

@end

# define DLog(fmt, …) NSLog((@”%s [Line %d] %@”), __PRETTY_FUNCTION__, __LINE__, [NSString stringWithFormat:(fmt), ##__VA_ARGS__]);

hope this helps.

(Obvious, I know, but this gets me every time — and it takes me several minutes to figure out why the code won’t compile)

and add the DLog definition code. Remember that its always a good idea to back up any template files before you start modifying them

When you changed the code to #if DEBUG, the preprocessor now checks for the value of the DEBUG variable. When it’s zero, the following statements are ignored and when it’s anything but zero the following statements are included.

Both ways work equally well, and it’s more a style issue or personal preference, which one you use.