Standard library header <ciso646> (until C++20), <iso646.h>

This header was originally in the C standard library as <iso646.h>.

# Notes

In old or nonconforming compilers, using the alternative operator representations may still require including this header.

is removed in C++20. Corresponding <iso646.h> is still available in C++20.

Prior to C++20, including was sometimes used as a technique for obtaining definitions of implementation-specific library version macros without causing other effects. As of C++20, the header was added for this purpose.

Possible output: