}
void vlg_pid_file(Vlg *vlg, const char *pid_file){  Vstr_base *out = vlg->out_vstr;    if (out->len)    vlg_err(vlg, EXIT_FAILURE, "Data in vlg for pid_file\n");    if (!vstr_add_fmt(out, out->len, "%lu", (unsigned long)getpid()))  {    vstr_del(out, 1, out->len);    vlg_err(vlg, EXIT_FAILURE, "vlg_pid_file: %m\n");  }  if (!vstr_sc_write_file(out, 1, out->len,                          pid_file, O_WRONLY | O_CREAT | O_TRUNC, 0644, 0,NULL))  {    vstr_del(out, 1, out->len);    vlg_err(vlg, EXIT_FAILURE, "vlg_pid_file(%s): %m\n", pid_file);  }}