Subclause [diff.library] summarizes the explicit changes in headers,
definitions, declarations, or behavior between the C standard library
in the C standard and the parts of the C++ standard library that were
included from the C standard library.
There are no C++ headers for the C standard library's headers
<stdnoreturn.h> and <threads.h>,
nor are these headers from the C standard library headers themselves part of C++.
The C headers <complex.h> and
<tgmath.h> do not contain any of the content from
the C standard library and instead merely include other headers from the C++
standard library.
The tokens
and,
and_eq,
bitand,
bitor,
compl,
not,
not_eq,
or,
or_eq,
xor,
and
xor_eq
are keywords in C++ ([lex.key]),
and are not introduced as macros
by <iso646.h>.
Header <cstddef>
declares the names nullptr_t, byte, and to_integer,
and the operators and operator templates in ([support.types.byteops]),
in addition to the names declared in
<stddef.h> in the C standard library.