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