HP 3000 Manuals HP 3000 Manuals
Structure and Union Members
A member of a structure or a union can be referenced using either of two
operators: the period or the right arrow.
Syntax
postfix-expression . identifier
postfix-expression -> identifier
Description
Use the period to reference members of structures and unions directly.
Use the arrow operator to reference members of structures and unions
pointed to by pointers. The arrow operator combines the functions of
indirection through a pointer and member selection. If P is a pointer to
a structure with a member M, the expression P->M is identical to (*P).M.
The postfix-expression in the first alternative must be a structure or a
union. The expression is followed by a period (.) and an identifier.
The identifier must name a member defined as part of the structure or
union referenced in the postfix-expression. The value of the
expression is the value of the named member. It is an lvalue if the
postfix-expression is an lvalue.
If the postfix-expression is a pointer to a structure or a pointer to a
union, follow it with an arrow (composed of the - character followed by
the >) and an identifier. The identifier must name a member of the
structure or union which the pointer references. The value of the
primary expression is the value of the named member. The resulting
expression is an lvalue.
The . operator and the -> operator are closely related. If S is a
structure, M is a member of structure S, and &S is a valid pointer
expression, S.M is the same as (&S)->M.