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

istag Subroutine

Purpose

Indicates whether a given tag is used within the current open object.

Libraries

Graphics Library

C (libgl.a)

FORTRAN (libfgl.a)

C Syntax

Int32 istag(Int32 tag)

FORTRAN Syntax

LOGICAL FUNCTION ISTAG(tag)
INTEGER*4 tag

Description

The istag subroutine indicates whether a given tag number actually identifies an existing tag. The returned value is either True (1), if the tag is already in use, or False (0), if it is not. If there is no current open object, the result is undefined.

Note: This editing subroutine, itself, cannot be used to add to a display list.

Parameter

tag Specifies the tag to test.

Return Values

True Tag number is already in use.
False Tag number is not in use.

Implementation Specifics

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

Files

/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

Returning a unique integer for use as a tag number with the gentag subroutine.

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


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