std::ofstream，写入前检查文件是否存在

2022-01-07 00:00:00 stream c++ fstream ofstream std

我正在使用 C++ 在 Qt 应用程序中实现文件保存功能.

I am implementing file saving functionality within a Qt application using C++.

我正在寻找一种方法来检查所选文件是否在写入之前已经存在，以便我可以向用户提示警告.

I am looking for a way to check to see if the selected file already exists before writing to it, so that I can prompt a warning to the user.

我正在使用 std::ofstream 并且我不是在寻找 Boost 解决方案.

I am using an std::ofstream and I am not looking for a Boost solution.

推荐答案

这是我最喜欢的隐藏功能之一，我手头有很多用途.

This is one of my favorite tuck-away functions I keep on hand for multiple uses.

#include <sys/stat.h>
// Function: fileExists
/**
    Check if a file exists
@param[in] filename - the name of the file to check

@return    true if the file exists, else false

*/
bool fileExists(const std::string& filename)
{
    struct stat buf;
    if (stat(filename.c_str(), &buf) != -1)
    {
        return true;
    }
    return false;
}

如果您没有立即将文件用于 I/O 的意图，我发现这比尝试打开文件更有品味.

I find this much more tasteful than trying to open a file if you have no immediate intentions of using it for I/O.

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