freebsd man page for offsetof

OFFSETOF(3)						   BSD Library Functions 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 C89'').

BSD
								 February 18, 2010							       BSD