Annex D (normative) Compatibility features [depr]

D.11 C headers [depr.c.headers]

D.11.3 Header <iso646.h> synopsis [depr.iso646.h.syn]

The C++ header <iso646.h> is empty.
[Note 1:
and, and_­eq, bitand, bitor, compl, not_­eq, not, or, or_­eq, xor, and xor_­eq are keywords in C++ ([lex.key]).
— end note]