OPEN STRUCTURE(3P) — Kubota Pacfic Computer Inc. (29 February 1991)

NAME

OPEN STRUCTURE − create a new structure or begin editing an existing structure

SYNOPSIS

C Syntax

void
popen_struct ( struct_id )
Pintstruct_id;structure identifier

Required PHIGS Operating States

(PHOP, ∗, STCL, ∗)

DESCRIPTION

Purpose

If the specified structure exists, OPEN STRUCTURE opens the structure for editing. If the specified structure does not exist, PHIGS creates a new structure and opens it for editing.

C Input Parameter

struct_id
The identifier of the structure to open or create.

Execution

If the specified structure does not exist, a new empty structure is created and opened, and the element pointer is set to 0. If the structure specified does exist, the structure is opened for editing and the element pointer is set to the last element in the structure.

A structure consists of a sequence of numbered structure elements. A structure element may contain:

• The specification for an output primitive • Attribute selection • View selection • A modelling transformation • A reference to another structure • A name set or label • A generalized structure element • Application data

An element pointer in the open structure is used to reference specific structure elements. When a PHIGS function creates a new element, the current edit mode determines whether the new element is inserted after or replaces the element pointed to by the current element pointer. You can perform the following operations on the open structure:

• Add or delete structure elements • Copy all elements from another structure • Inquire about the current element type and size or the current element content • Change the position of the element pointer • Inquire the current position of the element pointer

The PHIGS state list stores the identifier for the currently open structure, the position of the current element pointer, the current edit mode, and a list of all structure identifiers in use.

ERRORS

006Ignoring function, function requires state (PHOP, ∗, STCL, ∗)

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