6 ms·
`#define _CAT(A,B) A##B` is going to invoke undefined behaviour, I think: """ None of these macro names, nor the identifier `defined`, shall be the subject of
by endgame 16y ago
`#define _CAT(A,B) A##B` is going to invoke undefined behaviour, I think:
"""
None of these macro names, nor the identifier `defined`, shall be the subject of a #define or a #undef preprocessing directive. Any other predefined macro names shall begin with a leading underscore followed by an uppercase letter or a second underscore.
"""
(s6.10.8)