Re: How to create another lua_State in pthread?
- From: Mike Pall <mike-1301@xxxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Fri, 25 Jan 2013 14:39:39 +0100
Hiroaki Nakamura wrote:
> Now I am trying to get the callback function defined in another Lua state
> and call pthread_create with the callback address.
You must cast the Lua function ('hello') to a C function pointer
and then to a number in the other state and then convert it back
to a function pointer in the main state.
Patch attached.
--Mike
--- thread2.lua.orig
+++ thread2.lua
@@ -39,7 +39,7 @@
static const int LUA_GLOBALSINDEX = -10002;
void lua_getfield(lua_State *L, int index, const char *k);
-const void *lua_topointer(lua_State *L, int index);
+ptrdiff_t lua_tointeger(lua_State *L, int index);
void lua_settop(lua_State *L, int index);
]]
@@ -49,16 +49,18 @@
assert(L ~= nil)
C.luaL_openlibs(L)
assert(C.luaL_loadstring(L, [[
-function hello()
+local ffi = require("ffi")
+local function hello()
print("Hello from another Lua state!")
end
print(hello)
+cb_hello = tonumber(ffi.cast('intptr_t', ffi.cast('void *(*)(void *)', hello)))
]]) == 0)
assert(C.lua_pcall(L, 0, 1, 0) == 0)
-C.lua_getfield(L, C.LUA_GLOBALSINDEX, 'hello')
-local func_ptr = C.lua_topointer(L, -1);
+C.lua_getfield(L, C.LUA_GLOBALSINDEX, 'cb_hello')
+local func_ptr = C.lua_tointeger(L, -1);
print('func_ptr', func_ptr)
C.lua_settop(L, -2);
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