It seems pretty good at matching parens and braces for C code, although it decided it was finished before outputting the closing brace for the function (the prompt was just the signature):

  void send_file(int* fd) { 
    int file_type; 
    char *file_name; 
    size_t name_len; 
    FILE *fp; 
    char *name = NULL; 
    if(fmt::error_code != 0) 
      return error("Could not set file type"); 
    fp = &file->fp; 
    size_t file_size = fprintf(fp, "%02x", fp->fname); 
    if(fp->fname == fp->fname || _FTP_FILE_TYPE == 0) { 
      fp->fp->fname = 0; // Do nothing for errors 
    } 
    /* Write some info to fp */ 
    fp->fp->fd = calloc(1, fd) + (1 + file_size); 
    fp->fp->sig = calloc(1, &file->sig); 
    fp->fp->buf = (int *)((size_t)sizeof(*fp)); 
    /* Make sure fp isn't open */ 
    if(!fp->closed) { 
      // Close fd with error() 
      fp = new(FTP_FDCALLTYPE) void(1); 
      fp->fdclose((void *)&fp); 
      return; 
    } 
    fp->fp->buf_len = file_size; 
    fp->fp->name = name; 
    file_name = name; 
    fp->fp->cwd = nullptr; 
    /* Don't close fd after this point */ 
    fp->fp->fdclose(fprintf(f, "fd open", TRUE));

Not too bad, but I'm not worried about losing my job to a language model anytime soon.