NSFileManager used log
Usage
AppDelegate.m
NSString *logFilePath = [LogDataPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.log",[NSDate date]]];
freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stderr);
#optional
NSError *error;
NSString * LogDataPath = [[PRNUtils documentsDirectoryPath]stringByAppendingPathComponent:[NSString stringWithFormat:@"%@.Logs",@""]];
if (![[NSFileManager defaultManager] fileExistsAtPath:LogDataPath]){
[[NSFileManager defaultManager] createDirectoryAtPath:LogDataPath withIntermediateDirectories:NO attributes:nil error:&error]
}