Chapter 4. Miscellaneous Structure Elements

This section describes subroutines which generate structure elements which are not related to primitives or primitive attributes. The subroutines in this section generate structure execution and return elements and application data elements used to store application specific information.

GPCEXS - Conditional Execute Structure

Purpose

Use GPCEXS to insert a Conditional Execute Structure structure element into the open structure following the element pointer or to replace the element pointed at by the element pointer with a Conditional Execute Structure structure element depending on the current edit mode.

If the specified structure identifier does not exist, then the graPHIGS API creates a new empty structure.

If the current condition flags selected by the mask parameter satisfy the specified criteria, then the graPHIGS API executes the specified structure according to the specified execution mode. Otherwise, no action is taken, and the element count is incremented.

The condition flag is a 32-bit bit string. Each bit is defined as follows:

    0                        15  16                       29  30     31
    --------------------------------------------------------------------------
    |                           |                            | cull |  prune |
    | reserved for application  |          reserved          | flag |  flag  |
    --------------------------------------------------------------------------
  High bit                                                               Low bit

Note:

Not all GSEs are supported on all workstations. Use the Inquire List of Generalized Structure Elements (GPQGSE) inquiry subroutine to determine the GSEs which are supported by an open workstation. See also the workstation descriptors in The graPHIGS Programming Interface: Technical Reference

Parameters