On Sun, 20 Feb 2011 20:25:43 -0500, Edward Diener wrote:
I think Paul Mensonides may be right and there is no foolproof way to check for a completely empty parameter list even using variadic macros. Further ideas ?
Trust me, I am right. About the best you can do is prohibit input that terminates in a function-like macro name. You can generally detect emptiness *except* for that case. However, DATA_SIZE() => 0 is ill-conceived. An empty argument is still an argument to the preprocessor. A better correlation is: DATA_SIZE(,,) => 3 DATA_SIZE(,) => 2 DATA_SIZE() => 1 This is yet another reason why variadic content doesn't make for a good data structure. There is no way to denote the empty sequence. For all others, there are ways: (,,) // 3-element tuple (,) // 2-element tuple () // 1-element tuple // 0-element tuple (blank) ()()() // 3-element seq ()() // 2-element seq () // 1-element seq // 0-element seq (blank) Regards, Paul Mensonides