关于调试日志Log

 __VA_ARGS__  是一个可变参数的宏，这个可变参数的宏是新的C99规范中新增的，目前似乎只有gcc支持（VC6.0的编译器不支持）。宏前面加上##的作用在于，当可变参数的个数为0时，这里的##起到把前面多余的","去掉的作用,否则会编译出错

__FILE__  %s   宏在预编译时会替换成当前的源文件名，当前源代码文件全路径

__FUNCTION__宏在预编译时会替换成当前的函数名称

__func__%s 当前函数签名

__LINE__ %d 在源代码文件中当前所在行数，宏在预编译时会替换成当前的行号

__PRETTY_FUNCTION__ %s 像 __func__，但是包含了C++代码中的隐形类型信息

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
    //连接xcode时可以从监视器中看日志 没连接时Log日志会输出到文件中，
    [self redirectNSLogToDocumentFolder];
    return YES;
}

- (void)redirectNSLogToDocumentFolder
{
    //如果已经连接Xcode调试则不输出到文件
//    if(isatty(STDOUT_FILENO)) {
//        return;
//    }
    
//    UIDevice *device = [UIDevice currentDevice];
//    if([[device model] hasSuffix:@"Simulator"]){ //在模拟器不保存到文件中
//        return;
//    }
    
    //将NSlog打印信息保存到Document目录下的Log文件夹下
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *logDirectory = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Log"];
    
    NSFileManager *fileManager = [NSFileManager defaultManager];
    BOOL fileExists = [fileManager fileExistsAtPath:logDirectory];
    if (!fileExists) {
        [fileManager createDirectoryAtPath:logDirectory  withIntermediateDirectories:YES attributes:nil error:nil];
    }
    
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"]];
    [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"]; //每次启动后都保存一个新的日志文件中
    NSString *dateStr = [formatter stringFromDate:[NSDate date]];
    NSString *logFilePath = [logDirectory stringByAppendingFormat:@"/%@.log",dateStr];
    
    // 将log输入到文件
    freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stdout);
    freopen([logFilePath cStringUsingEncoding:NSASCIIStringEncoding], "a+", stderr);
    
    //未捕获的Objective-C异常日志
    NSSetUncaughtExceptionHandler (&UncaughtExceptionHandler);
}

void UncaughtExceptionHandler(NSException* exception)
{
    NSString* name = [ exception name ];
    NSString* reason = [ exception reason ];
    NSArray* symbols = [ exception callStackSymbols ]; // 异常发生时的调用栈
    NSMutableString* strSymbols = [ [ NSMutableString alloc ] init ]; //将调用栈拼成输出日志的字符串
    for ( NSString* item in symbols )
    {
        [ strSymbols appendString: item ];
        [ strSymbols appendString: @"\r\n" ];
    }
    
    //将crash日志保存到Document目录下的Log文件夹下
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *logDirectory = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Log"];
    
    NSFileManager *fileManager = [NSFileManager defaultManager];
    if (![fileManager fileExistsAtPath:logDirectory]) {
        [fileManager createDirectoryAtPath:logDirectory  withIntermediateDirectories:YES attributes:nil error:nil];
    }
    
    NSString *logFilePath = [logDirectory stringByAppendingPathComponent:@"UncaughtException.log"];
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"]];
    [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    NSString *dateStr = [formatter stringFromDate:[NSDate date]];
    
    NSString *crashString = [NSString stringWithFormat:@"<- %@ ->[ Uncaught Exception ]\r\nName: %@, Reason: %@\r\n[ Fe Symbols Start ]\r\n%@[ Fe Symbols End ]\r\n\r\n", dateStr, name, reason, strSymbols];
    //把错误日志写到文件中
    if (![fileManager fileExistsAtPath:logFilePath]) {
        [crashString writeToFile:logFilePath atomically:YES encoding:NSUTF8StringEncoding error:nil];
    }else{
        NSFileHandle *outFile = [NSFileHandle fileHandleForWritingAtPath:logFilePath];
        [outFile seekToEndOfFile];
        [outFile writeData:[crashString dataUsingEncoding:NSUTF8StringEncoding]];
        [outFile closeFile];
    }
    
    //把错误日志发送到邮箱
//    NSMutableString *mailUrl = [NSMutableString string];
//    [mailUrl appendString:@"mailto:xxxxxxxxx@qq.com"];
//    [mailUrl appendString:@"?subject=程序异常崩溃，请配合发送异常报告，谢谢合作！"];
//    [mailUrl appendFormat:@"&body=%@", crashString];
//    // 打开地址
////    NSString *mailPath = [mailUrl stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
//    NSString *mailPath = [mailUrl stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet characterSetWithRange:NSMakeRange(0, mailUrl.length)]];
//    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:mailPath]];
}

日志code