NSLog()到控制台和文件 [英] NSLog() to both console and file

问题描述

我想将NSog()重定向到文件，但仍要在控制台中查看输出. 我知道stderr可以使用以下命令重定向到文件:

I would like to redirect NSog() to file, but still to see the output in console. I am aware that stderr can be redirected to file using:

freopen("file.log", "a+", stderr);

但是将其重定向到文件后，该日志不再显示在控制台输出中.

but after redirecting it to file, the log is no more shown in the console output.

我可以在NSLog()周围构建自定义包装，但是在应用程序崩溃时，不会获得写入到stderr的已记录崩溃日志.

I could build a custom wrapper around NSLog() but I would not get logged crash logs that are written to stderr in the moment of app crash.

我也在尝试使用dup()和其他方法来复制文件描述符，但是输出是在文件或控制台中的以太，两者都不是.

I was also experimenting with dup() and other methods for duplicating file descriptors, but the output was ether in file or in console, never in both.

在这里提出了类似的问题: 在iPhone上将stderr写入文件和控制台 但没有被接受的答案，也没有建议使用NSLog()包装器.

Similar questions was asked here: Write stderr on iPhone to both file and console but without accepted answer, or with suggestion to use a NSLog() wrapper.

有人对如何管理这项工作有想法吗? 提前感谢.

Has anyone an idea on how to manage this work? Thanx in advance.

更新:重定向最重要的部分是将系统错误日志( stderr )写入控制台和文件.

UPDATE: The most important part of redirecting is to have system error logs (stderr) written to both console and file.

推荐答案

According to the docs, you will need a custom log facility.

您至少需要一个函数，该函数接受可变参数并打印到NSLog和fprintf中，例如:

You need at a minimum, a function that takes variadic arguments and printd to NSLog and fprintf, something like:

void myLog(NSString* format, ...)
{
    va_list argList;
    va_start(argList, format);
    NSString* formattedMessage = [[NSString alloc] initWithFormat: format arguments: argList];
    va_end(argList);
    NSLog(@"%@", formattedMessage);
    fprintf(myFileDescriptor, "%s\n", [formattedMessage UTF8String]);
    [formattedMessage release]; // if not on ARC
}

或者有可可记录框架.

寻找特定的可可记录框架

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