Re: Hand over global userdata to LUA-called C-function
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- Subject: Re: Hand over global userdata to LUA-called C-function
- From: Owen Shepherd <owen.shepherd@...>
- Date: 2013年5月23日 15:04:13 +0100
Satz Klauer wrote:
int my_lua_called_c_fct(lua_State *L)
there seems to be "L" where I could get these user data from. But how
can I put the data to "L" during initialisation and how can I retrieve
them within that function?
These are some configuration-data that are required to execute
my_lua_called_c_fct()...
Thanks!
Normally you would stash the userdata in the registry table. Two options exist for this; the first is to use a string key and retrieve it with code along the lines of:
lua_pushliteral(L, "mykey");
lua_gettable(L, LUA_REGISTRYINDEX);
MyType* data = "" lua_touserdata(L, -1);
Another alternative, slightly faster (because you don't have to intern the string each time) is to use a light user data pointed at a glo
bal constant for the key:
static const char* mykey = "This string is completely ignored";
...
lua_pushlightuserdata(L, mykey);
lua_gettable(L, LUA_REGISTRYINDEX);
MyType* data = "" lua_touserdata(L, -1);
The registry table is a table that is global to the interpreter (and not normally visible to script)