Re: Lua C API can't be used from other languages without C wrappers
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- Subject: Re: Lua C API can't be used from other languages without C wrappers
- From: Andrew Gierth <andrew@...>
- Date: 2018年2月21日 15:28:56 +0000
>>>>> "albertmcchan" == albertmcchan <albertmcchan@yahoo.com> writes:
albertmcchan> Had not expected calling B shared the same lua stack.
albertmcchan> Is there a way to force calling B, C, ... with a new
albertmcchan> stack ? (like in lua ?)
Of course there is, you use lua_pushcfuncfion and lua_call, as I pointed
out to you before.
int B(lua_State *L)
{
lua_settop(L, 0);
lua_pushstring(L, "foo!");
return 1;
}
int A(lua_State *L)
{
/* stack currently has args of A if any */
lua_pushstring(L, "bar!");
/* this calls B in A's stack frame, so it will clobber the
* string pushed above and any args, leaving A's stack with
* just B's "foo!" on it
*/
B(L);
/* but this calls B on a brand new stack frame of its own,
* so the existing "foo!" remains on the stack and another
* one is pushed on top
*/
lua_pushcfunction(L, B);
lua_call(L, 0, 1); /* 0 args, 1 result */
/* stack now has just "foo!", "foo!" */
return 2;
}
This is how you do it if B and A both need to be independently callable
from Lua but A needs to call B.
--
Andrew.