Re: Caveat with lua_pushlightuserdata(L, (void *)&key)

[Andreas Stenius <kaos@...>]

Julien Cugnière skrev:
> Anyway, here is a simple way to ensure that your constants are unique
> (assuming this legal C):
>
>    static const void* regkey1 = &regkey1;
>    static const void* regkey2 = &regkey2;

No, &regkey1 is not a constant expression, although the result is constant.

I would use the __FILE__ and __LINE__ macros to get unique values,
unless space is an issue.

Something like:

#define STRINGIFY(a)	#a
#define SAPPEND(s,i)	s "" STRINGIFY(i)
#define UNIQUE_KEY	SAPPEND(__FILE__, __FILE__)

static const char* unique_key = UNIQUE_KEY;

// just make sure not to have more than one key-macro per line


Regards,
	Andreas