如何检测何时重定向输出？ [英] How do I detect when output is being redirected?

问题描述

我有一个用C编写的Win32应用程序，可以通过printf（）将其控制台输出重定向到日志文件。

I have a Win32 application written in C that can have its console output via printf() redirected to a log file.

它如果我可以安装我的应用程序，那就太好了。

It would be nice if I could have my app. detect if it had been started with or without a redirect '>'.

有什么想法吗？

推荐答案

汤姆，谢谢您的输入。

我做了一些实验，发现这对我有用。

I did some experiments and found this works for me..

fpost_t pos ;

fgetpos (stdout, & pos) ;

将应用程序的输出重定向到文件时，fgetpos（）会将pos设置为零。这是有道理的，因为它为您提供了新近打开的stderr。 编辑：实际上，如果文本已被重定向到日志/文件，则返回的值可能是正整数。因此，在您的代码中，您将遇到类似 if（pos> = 0）bfRedirected = TRUE;

When an application's output is being redirected to a file, fgetpos() sets 'pos' to zero. It makes sense since its freshly opened stderr for you. Actually, the value returned may be a positive integer if text has already been redirected to the log/file. So in your code you'd have something like "if (pos >= 0) bfRedirected = TRUE ;"

当应用程序的输出未重定向时，它会控制台设备-不是文件，因此fgetpos（）会将'pos'设置为-1。

When an application's output is not being redirected - it's going to the console device - not a file, so fgetpos() will set 'pos' to -1.

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