The reference manual as well as previous behaviors say that CCLuaStack::executeString() should return 0 if no error occurs. What I’m seeing from the following code is that executeString returns 0 on error, and returns the return value from lua script on success, and that return value might as well be 0. There is good way to tell an error without modifying this then?
int CCLuaStack::executeString(const char *codes)
{
luaL_loadstring(m_state, codes);
return executeFunction(0);
}
int CCLuaStack::executeFunction(int numArgs)
{
int functionIndex = -(numArgs + 1);
if (!lua_isfunction(m_state, functionIndex))
{
CCLOG("value at stack [%d] is not function", functionIndex);
lua_pop(m_state, numArgs + 1); // remove function and arguments
return 0;
}
int traceback = 0;
lua_getglobal(m_state, "__G__TRACKBACK__"); /* L: ... func arg1 arg2 ... G */
if (!lua_isfunction(m_state, -1))
{
lua_pop(m_state, 1); /* L: ... func arg1 arg2 ... */
}
else
{
lua_insert(m_state, functionIndex - 1); /* L: ... G func arg1 arg2 ... */
traceback = functionIndex - 1;
}
int error = 0;
++m_callFromLua;
error = lua_pcall(m_state, numArgs, 1, traceback); /* L: ... [G] ret */
--m_callFromLua;
if (error)
{
if (traceback == 0)
{
CCLOG("[LUA ERROR] %s", lua_tostring(m_state, - 1)); /* L: ... error */
lua_pop(m_state, 1); // remove error message from stack
}
else /* L: ... G error */
{
lua_pop(m_state, 2); // remove __G__TRACKBACK__ and error message from stack
}
return 0;
}
// get return value
int ret = 0;
if (lua_isnumber(m_state, -1))
{
ret = lua_tointeger(m_state, -1);
}
else if (lua_isboolean(m_state, -1))
{
ret = lua_toboolean(m_state, -1);
}
// remove return value from stack
lua_pop(m_state, 1); /* L: ... [G] */
if (traceback)
{
lua_pop(m_state, 1); // remove __G__TRACKBACK__ from stack /* L: ... */
}
return ret;
}