NAME

LABEL − create a structure element containing a label identifier

SYNOPSIS

C Syntax

void
plabel ( label_id )
Pintlabel_id;label identifier

Required PHIGS Operating States

(PHOP, ∗, STOP, ∗)

DESCRIPTION

Purpose

The LABEL subroutine puts a structure element containing a label identifier into the currently open structure. Labels are used to mark locations within a structure. 

If the current edit mode is INSERT, the LABEL element is inserted into the currently open structure after the element currently pointed to by the element pointer. If the edit mode is REPLACE, the LABEL element replaces the element pointed to. In either case, the element pointer is updated to point to the new LABEL element. 

C Input Parameter

label_id
The label identifier is used by other subroutines to reference the label element’s location in the structure.

Execution

The LABEL element is a marker within the structure. When the structure is traversed, LABEL elements are ignored.  LABEL elements are used by the SET ELEMENT POINTER AT LABEL and DELETE ELEMENTS BETWEEN LABELS subroutines to identify locations within a structure. The labels allow you to locate an element or group of elements even if structure editing changes the numbering of elements within the structure.  For example, you may wish to bracket a sequence of related elements in a structure with labels.  Label identifiers need not be unique in a structure. The search for a label within a structure is always from the element after the current position of the element pointer toward the end of the structure. Subroutines which refer to labels reference the next occurrence of the specified label within the structure. If the specified label is not found before the end of the structure, an error is generated.

ERRORS

005Ignoring function, function requires state (PHOP, ∗, STOP, ∗)

SEE ALSO

SET ELEMENT POINTER AT LABEL (3P)
DELETE ELEMENTS BETWEEN LABELS (3P)
INQUIRE ELEMENT POINTER (3P)
ELEMENT SEARCH (3P)

September 02, 1992