OFFSETOF(3) OpenBSD Programmer's Manual OFFSETOF(3)NAME
offsetof - offset of a structure member
SYNOPSIS
#include <stddef.h>
size_t
offsetof(type, member);
DESCRIPTION
The offsetof() macro expands to an integer constant expression of type
size_t and yields the offset, in bytes, of the field member from the
start of the structure type.
A compiler error will result if member is not aligned to a byte boundary
(i.e. it is a bit-field).
STANDARDS
The offsetof() macro conforms to ANSI X3.159-1989 (``ANSI C'').
OpenBSD 4.9 February 18, 2010 OpenBSD 4.9