Indicates whether a given tag is used within the current open object.
FORTRAN (libfgl.a)
Int32 istag(Int32 tag)
LOGICAL FUNCTION ISTAG(tag) INTEGER*4 tag
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.
| tag | Specifies the tag to test. |
| True | Tag number is already in use. |
| False | Tag number is not in use. |
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. |
Returning a unique integer for use as a tag number with the gentag subroutine.
AIX Graphics Library Overview and Creating Objects (Display Lists).