执行命令，获取输出

x.cpp

// https://stackoverflow.com/questions/478898/how-do-i-execute-a-command-and-get-the-output-of-the-command-within-c-using-po
std::string exec(const char* cmd)
{
    std::array<char, 128> buffer;
    std::string result;
    std::unique_ptr<FILE, decltype(&_pclose)> pipe(_popen(cmd, "r"), _pclose);
    if (!pipe) {
        throw std::runtime_error("popen() failed!");
    }
    while (fgets(buffer.data(), buffer.size(), pipe.get()) != nullptr) {
        result += buffer.data();
    }
    return result;
}
// https://stackoverflow.com/questions/52164723/how-to-execute-a-command-and-get-return-code-stdout-and-stderr-of-command-in-c
int execute(std::string cmd, std::string& output) {
    const int bufsize=128;
    std::array<char, bufsize> buffer;

    auto pipe = popen(cmd.c_str(), "r");
    if (!pipe) throw std::runtime_error("popen() failed!");

    size_t count;
    do {
        if ((count = fread(buffer.data(), 1, bufsize, pipe)) > 0) {
            output.insert(output.end(), std::begin(buffer), std::next(std::begin(buffer), count));
        }
    } while(count > 0);

    return pclose(pipe);
}