How to create a std::ofstream to a temp file?

I’ve done this function:

#include <stdlib.h>
#include <fstream>
#include <iostream>
#include <vector>

std::string open_temp(std::string path, std::ofstream& f) {
    path += "/XXXXXX";
    std::vector<char> dst_path(path.begin(), path.end());
    dst_path.push_back('\0');

    int fd = mkstemp(&dst_path[0]);
    if(fd != -1) {
        path.assign(dst_path.begin(), dst_path.end() - 1);
        f.open(path.c_str(), 
               std::ios_base::trunc | std::ios_base::out);
        close(fd);
    }
    return path;
}

int main() {
    std::ofstream logfile;
    open_temp("/tmp", logfile);
    if(logfile.is_open()) {
        logfile << "hello, dude" << std::endl;
    }
}

You should probably make sure to call umask with a proper file creation mask (I would prefer 0600)- the manpage for mkstemp says that the file mode creation mask is not standardized. It uses the fact that mkstemp modifies its argument to the filename that it uses. So, we open it and close the file it opened (so, to not have it opened twice), being left with a ofstream that is connected to that file.