2012-09-12 41 views
1

我試圖按照this question中所述重新定義打印功能。這裏是我的代碼:在lua中重新定義打印功能時出現問題

extern "C"{ 
#include <lua.h> 
#include <lauxlib.h> 
#include <lualib.h> 
} 

#include <iostream> 

using namespace std; 

lua_State* L; 

static int l_my_print(lua_State* L) { 
    int nargs = lua_gettop(L); 

    for (int i=1; i <= nargs; i++) { 
     if (lua_isstring(L, i)) { 
      cout << "!!!" << lua_tostring(L, i) << "!!!" << endl; 
     } 
    } 

    return 0; 
} 

static const struct luaL_Reg printlib [] = { 
    {"print", l_my_print}, 
    {NULL, NULL} /* end of array */ 
}; 

extern int luaopen_luamylib(lua_State *L) 
{ 
    lua_getglobal(L, "_G"); 
    luaL_register(L, NULL, printlib); 
    lua_pop(L, 1); 
} 


int main(){ 
    L = luaL_newstate(); 
    luaL_openlibs(L); 
    luaopen_luamylib(L); 

    luaL_dostring(L, "print(\"hello\")"); 

    lua_close(L); 

    return 0; 
} 

當我嘗試編譯代碼時,我得到:

$ g++ -I/usr/include/lua5.2 -o embed test.cpp -Wall -Wextra -llua5.2 
test.cpp:28:1: error: elements of array ‘const luaL_reg printlib []’ have incomplete type 
test.cpp:28:1: error: storage size of ‘printlib’ isn’t known 
test.cpp: In function ‘int luaopen_luamylib(lua_State*)’: 
test.cpp:33:34: error: ‘luaL_register’ was not declared in this scope 
test.cpp:35:1: warning: no return statement in function returning non-void [-Wreturn-type] 

誰能解釋這到底是怎麼發生的?我錯過了一個圖書館或什麼?

UPDATE

有人指出,該結構被稱爲luaL_Reg,不luaL_reg。這解決了我的第一個問題:

$ g++ -I/usr/include/lua5.2 -o embed test.cpp -Wall -Wextra -llua5.2 
test.cpp: In function ‘int luaopen_luamylib(lua_State*)’: 
test.cpp:33:34: error: ‘luaL_register’ was not declared in this scope 
test.cpp:35:1: warning: no return statement in function returning non-void [-Wreturn-type] 
+0

前兩個錯誤聽起來像是你缺少定義'struct luaL_reg'的頭文件。 –

回答

4

第一個錯誤:這是luaL_Reg,不luaL_reg

第二個錯誤: luaL_register已棄用(在Lua 5.2中),並且僅在包含Lua標頭之前定義了LUA_COMPAT_MODULE時纔可用。您應該使用luaL_setfuncs。

+0

修復了第一個錯誤。第二個呢? – ewok