6.16.1 stddef.h Types and Macros
ptrdiff_t Type
Type used to represent the difference in two pointer values.
Include
<stddef.h>
Remarks
The ptrdiff_t type is a signed integer type that is
used to represent the difference between two pointer values.
size_t Type
Type used to represent the result of the sizeof
operator.
Include
<stddef.h>
Remarks
The size_t type is an unsigned integer type that is
used to represent the size of an object, as returned by the sizeof
operator.
wchar_t Type
Type used to represent the values of the largest extended character set.
Include
<stddef.h>
Remarks
The wchar_t type is an integer type that is used to
represent the values of the largest extended character set.