c++ - How to check if a file exists (regardless of its file type)?

Edit: The problem wasn't with my c++. The problem was with how I was calling the shared library in GameMaker Studio, which was why it wasn't working.

I'm trying to detect whether a file exists, and I've tried many methods over the internet and none of them seem to work. Here's an example:

double file_exists(char *filename)
{
    std::ifstream infile(filename);
    return infile.good();
}

I assume it will only work with text files. for example, this won't work:

file_exists("/usr/bin/gedit");

...because that is a Linux executable.

I want a means to check whether a file exists regardless of its file type.

On Windows, this can easily be achieved like so:

double file_exists(char* filename)
{
    DWORD fileAtt = GetFileAttributesA(filename);
    if(fileAtt == INVALID_FILE_ATTRIBUTES)
        throw GetLastError();

    return (bool)((fileAtt&FILE_ATTRIBUTE_DIRECTORY) == 0);

}

But I'm on Linux and I need an equivalent of the above snippet that will work on Linux.