http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56825
--- Comment #4 from Evgeny Televitckiy <stelek at gmail dot com> 2013-04-04 06:41:38 UTC --- Ye, I thought it was something along those lines. Thanks for the clarification, now I understand the reason why this paragraph appear in standard. Yet, appealing to the end of your comment. I would expect ,##x construct to be an exception, especially that it has a totally different meaning then concatenating # or stringifying ##. Clearly one would expect: #define E3N(n, ar...) E3NI(_, ##ar, n, n, n) #define E3NI(a0, a1, a2, a3, ...) a1, a2, a3 #define USE_E3_ARG_R(n, ar...) (E3N(n, ar)) #define USE_E3_ARG_W(n, ar...) (E3N(n, ##ar)) and used: USE_E3_ARG_R(5, USE_E3_ARG_R(6, 7)); USE_E3_ARG_W(5, USE_E3_ARG_W(6, 7)); To produce the same result... In addition I wanted to add that it is not some virtual problem. I actually spent 3 hours of my life in that macro hell, trying to understand what went wrong with that macro,
