检查在Windows / Linux中对文件的写入权限 [英] Check for writing permissions to file in Windows/Linux

问题描述

我想知道如何检查是否对文件夹具有写入权限。

I would like to know how to check if I have write permissions to a folder.

我正在写一个C ++项目，我应该打印一些数据到result.txt文件，但我需要知道是否有权限。

I'm writing a C++ project and I should print some data to a result.txt file, but I need to know if I have permissions or not.

Linux和Windows之间的检查是否不同？因为我的项目应该在Linux上运行，目前我在Visual Studio中工作。

Is the check different between Linux and Windows? Because my project should run on Linux and currently I'm working in Visual Studio.

推荐答案

尝试打开文件并检查是否成功。如果没有，并且 errno （从标题 < cerrno> 设置为值 EACCES [yes，with one S]，那么您没有足够的权限。这应该同时适用于 Unix / Linux 和 Windows 。stdio的示例：

The portable way to check permissions is to try to open the file and check if that succeeded. If not, and errno (from the header <cerrno> is set to the value EACCES [yes, with one S], then you did not have sufficient permissions. This should work on both Unix/Linux and Windows. Example for stdio:

FILE *fp = fopen("results.txt", "w");
if (fp == NULL) {
    if (errno == EACCES)
        cerr << "Permission denied" << endl;
    else
        cerr << "Something went wrong: " << strerror(errno) << endl;
}

Iostreams的工作方式略有不同，AFAIK，他们不保证设置

Iostreams will work a bit differently. AFAIK, they do not guarantee to set errno on both platforms, or report more specific errors than just "failure".

正如Jerry Coffin写的那样，不要依赖这些错误在单独的访问测试功能，因为您的程序将容易出现竞争条件和安全漏洞。

As Jerry Coffin wrote, don't rely on separate access test functions since your program will be prone to race conditions and security holes.

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