caching userdata pointers, lua_pushuserdata?
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- Subject: caching userdata pointers, lua_pushuserdata?
- From: Kriss <Kriss@...>
- Date: 2005年7月26日 01:45:46 +0100
I was just thinking about tidying up some code and want to do the
following.
cache a pointer returned from lua_touserdata() on the C side (I am
already doing this anyway)
at some point later on, push that userdata onto the stack to be used as
a table look up key, I can guarantee that the userdata will not have
been GCd at this point. At the moment I am using a unique integer as a
table key, but it would be simpler to use the userdata instead.
however there is no lua_pushuserdata()
Is it safe just to use a modified version of lua_newuserdata() that
doesnt allocate any new userdata but takes a previously allocated
pointer and pushes it on the stack?
EG some untested 5.0 code :)
LUA_API void lua_pushuserdata (lua_State *L, void *data) {
lua_lock(L);
luaC_checkGC(L);
setuvalue(L->top, ((Udata *)(data))-1);
api_incr_top(L);
lua_unlock(L);
}
or is there some more magic surrounding userdata I should be aware of.
--
Kriss
http://XIXs.com -><- http://www.WetGenes.com