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GL3.2 for AIX: Graphics Library (GL) Technical Reference

objreplace Subroutine


Replaces existing display list routines with new ones.


Graphics Library

C (libgl.a)

FORTRAN (libfgl.a)

C Syntax

void objreplace(Int32 tag)




The objreplace subroutine positions the editing pointer at the location specified by the tag parameter. All subsequent graphics primitives overwrite the display list at the current location of the editing pointer.

Each graphics primitive increments the editing pointer to point immediately after the most recently inserted subroutine (in the same way that the cursor advances in an ordinary text editing facility as letters are typed).

The objreplace subroutine requires that the new subroutine and the subroutine being overwritten are the same length; otherwise, this or other subroutines in the display list may be partially overwritten, resulting in unpredictable drawing when the object is executed. In general, no two dissimilar GL subroutines are the same length.

The objreplace subroutine is best used for changing the parameter values of a subroutine that has already been compiled into a display list. Use the objdelete and objinsert subroutines for more general replacement.

Use the closeobj subroutine to terminate editing and close up the current display list, or one of the positioning subroutines (objdelete, objinsert, or objreplace) to reposition the editing pointer.as a quick method of creating a new version of a routine.

Note: This editing subroutine itself cannot be added to a display list.


tag Specifies a tag within the object definition to be edited.

Implementation Specifics

This subroutine is part of GL in the AIXwindows Environment/6000 Version 1, Release 2 with AIXwindows/3D Feature.


/usr/include/gl/gl.h Contains C language constant and variable type definitions for GL.
/usr/include/gl/fgl.h Contains FORTRAN constant and variable type definitions for GL.

Related Information

Closing an object with the closeobj subroutine.

Opening an object for editing with the editobj subroutine.

Marking a location in the display list with the maketag subroutine.

Deleting a routine from an object with the objdelete subroutine.

Inserting a routine into an object with the objinsert subroutine.

AIX Graphics Library Overview and Creating Objects (Display Lists).

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