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

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• Subject: Re: Caveat with lua_pushlightuserdata(L, (void *)&key)
• From: Andreas Stenius <kaos@...>
• Date: 2006年6月26日 10:33:34 +0200

---

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

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• Follow-Ups:
  • Re: Caveat with lua_pushlightuserdata(L, (void *)&key), David Jones

• References:
  • Caveat with lua_pushlightuserdata(L, (void *)&key), Mike Pall
  • Re: Caveat with lua_pushlightuserdata(L, (void *)&key), Julien Cugnière

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