由 Lua 取得值

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由 dostring 傳回值

問題：我要如何從 C 方面取得由 lua_dostring 執行的 Lua 程式區塊的回傳值，亦即如何取得由 Lua dostring 函式回傳的結果？

(lhf) 就像任何函式的回傳值一樣。以下是一個範例

lua_State *L=lua_open(0);
printf( "%d\n", lua_gettop(L) );
lua_dostring(L, "return 1,'a'" );
printf( "%d\n", lua_gettop(L) );
printf( "%s\n", lua_tostring(L,-2) );
printf( "%s\n", lua_tostring(L,-1) );

returnone.c

#include <lua.h>
#include <lualib.h>

int main()
{
  lua_State *L=lua_open();
  printf( "%d\n", lua_gettop(L) );
  lua_dostring(L, "return 1,'a'" );
  printf( "%d\n", lua_gettop(L) );
  printf( "%s\n", lua_tostring(L,-2) );
  printf( "%s\n", lua_tostring(L,-1) );
  return 0;
}

編譯

gcc -o returnone returnone.c -I/usr/include/lua50 -llua50 -llualib50

執行： # ./returnone

0
2
1
a

lua_dostring() 已不存在

returnone.c

#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>

int main()
{
   lua_State *L = luaL_newstate();
   char buff[] = "return 1,'a'";
   int error;
   printf( "%d\n", lua_gettop(L) );
   error = luaL_loadbuffer(L, buff, strlen(buff), "my test") || lua_pcall(L, 0, LUA_MULTRET, 0);
   if (error) {
      fprintf(stderr, "%s", lua_tostring(L, -1));
      lua_pop(L, 1);  /* pop error message from the stack */
   }
   printf( "%d\n", lua_gettop(L) );
   printf( "%s\n", lua_tostring(L,-2) );
   printf( "%s\n", lua_tostring(L,-1) );
   return 0;
}