Function io_popen

depends/lua/src/liolib.c:276–285

static int io_popen (lua_State *L) {
  const char *filename = luaL_checkstring(L, 1);
  const char *mode = luaL_optstring(L, 2, "r");
  LStream *p = newprefile(L);
  luaL_argcheck(L, ((mode[0] == 'r' || mode[0] == 'w') && mode[1] == '\0'),
                   2, "invalid mode");
  p->f = l_popen(L, filename, mode);
  p->closef = &io_pclose;
  return (p->f == NULL) ? luaL_fileresult(L, 0, filename) : 1;
}


static int io_tmpfile (lua_State *L) {