istag(3G)

NAME
     istag - returns whether a tag exists in the current open object

C SPECIFICATION
     Boolean istag(t)
     Tag t;

PARAMETERS
     t   expects the tag identifier that you want to test.

FUNCTION RETURN VALUE
     There are two possible return values for this function:

     TRUE    indicates that tag t exists in the current open object.

     FALSE   indicates that tag t does not exist in the current open object.

     The return value is undefined if no object is currently open for editing.

DESCRIPTION
     istag returns whether or not a tag is exists in the object currently open
     for editing.  If maketag has been called to create a tag, and deltag has
     not been called to delete it, istag returns TRUE for it.

SEE ALSO
     deltag, gentag, isobj, maketag

NOTE
     This routine is available only in immediate mode.