
    // Functions to return standard streams 'stdin', 'stdout' and 'stderr'.
    // (throw a CImgIOException when macro 'cimg_use_r' is defined).
    inline FILE* _stdin(const bool throw_exception) {
#ifndef cimg_use_r
      cimg::unused(throw_exception);
      return stdin;
#else
      if (throw_exception) {
        cimg::exception_mode(0);
        throw CImgIOException("cimg::stdin(): Reference to 'stdin' stream not allowed in R mode "
                              "('cimg_use_r' is defined).");
      }

     
     
    inline FILE* _stdin(const bool throw_exception) {
#ifndef cimg_use_r
      cimg::unused(throw_exception);
      return stdin;
#else
      if (throw_exception) {
        cimg::exception_mode(0);
        throw CImgIOException("cimg::stdin(): Reference to 'stdin' stream not allowed in R mode "
                              "('cimg_use_r' is defined).");
      }