Re: Register Lua callback functions from within Lua to C++

["Jerome Vuarand" <jerome.vuarand@...>]

2008/11/10 Michael Bauroth <Michael.Bauroth@falcom.de>:
> Hi, me once more. Have found out, that the code works very well (another
> error confused me here). The remaining question is, how to pass a additional
> parameter (in my special case the sender object), when I trigger the
> callback?
>
> // push function
> lua_rawgeti( L, LUA_REGISTRYINDEX, m_CbOnMouseDown );
>
> // push parameter(s)
> lua_rawgeti( L, LUA_REGISTRYINDEX, this );
> // XXX doesn't work, needs an integer here  :(
>
> // call function
> if ( lua_pcall( L, 1, LUA_MULTRET, 0 ) != 0 )
> {
>    TRACE( _T( "Error calling LUA callback OnMouseDown\n" ) );
> }

Use lua_pushlightuserdata or lua_newuserdata to pass a pointer to Lua.
For example:

lua_rawgeti(L, LUA_REGISTRYINDEX, m_CbOnMouseDown);
lua_pushlightuserdata(L, this);
if ( lua_pcall( L, 1, LUA_MULTRET, 0 ) != 0 )
{
    TRACE( _T( "Error calling LUA callback OnMouseDown\n" ) );
}