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X 8.1.15.3 LABEL Declarative




X The LABEL declarative provides user label-handling procedures.


X >_Workstation_> Under AIX, OS/2, and Windows, USE...AFTER...LABEL
X PROCEDURE is not supported. If encountered, they are ignored and a
X warning message is issued. <_Workstation_<


 X  ___ Format 2--USE (LABEL Declarative) __________________________________ 
 X |                                                                        |
 X | >>__USE__ ________ __AFTER__ __________ __ ___________ __ ______ ____> |
 X |          |_GLOBAL_|         |_STANDARD_|  |_BEGINNING_|  |_FILE_|      |
 X |                                           |_ENDING____|  |_REEL_|      |
 X |                                                          |_UNIT_|      |
   |                                                                        |
 X |                               <_____________                           |
 X | >__LABEL PROCEDURE__ ____ __ ___file-name-1_|_ _____________________>< |
 X |                     |_ON_|  |_INPUT___________|                        |
 X |                             |_OUTPUT__________|                        |
 X |                             |_I-O_____________|                        |
 X |                             |_EXTEND__________|                        |
   |                                                                        |
   |________________________________________________________________________|

X AFTER

X User labels follow standard file labels, and are to be processed.


X The labels must be listed as data-names in the LABEL RECORDS clause in
X the file description entry for the file, and must be described as
X level-01 data items subordinate to the file entry.


X If neither BEGINNING nor ENDING is specified, the designated
X procedures are executed for both beginning and ending labels.


X If FILE, REEL, or UNIT is not included, the designated procedures are
X executed both for REEL or UNIT, whichever is appropriate, and for FILE
X labels.


X FILE

X The designated procedures are executed at beginning-of-file (on the
X first volume) and/or at end-of-file (on the last volume) only.


X REEL

X The designated procedures are executed at beginning-of-volume (on each
X volume except the first) and/or at end-of-volume (on each volume
X except the last).


X The REEL option is not applicable to direct-access files.


X UNIT

X The designated procedures are executed at beginning-of-volume (on each
X volume except the first) and/or at end-of-volume (on each volume
X except the last).


X The UNIT phrase is not applicable to files in the random access mode,
X because only FILE labels are processed in this mode.


X file-name-1

X Can appear in different specific arrangements of the format. However,
X appearance of a file-name in a USE statement must not cause the
X simultaneous request for execution of more than one USE declarative.


X file-name-1 must not represent a sort file.


X If the file-name-1 option is used, the file description entry for
X file-name must not specify a LABEL RECORDS ARE OMITTED clause.


X When the INPUT, OUTPUT, or I-O options are specified, user label
X procedures are executed as follows:


X If the INPUT, OUTPUT, or I-O phrase is specified, and an input, output, or
X I-O file, respectively, is described with a LABEL RECORDS ARE OMITTED
X clause, the USE procedures do not apply. The standard system procedures
X are performed:


X Within the procedures of a USE declarative in which the USE sentence
X specifies an option other than file-name, references to common label items
X need not be qualified by a file-name. A common label item is an
X elementary data item that appears in every label record of the program,
X but does not appear in any data records of this program. Such items must
X have identical descriptions and positions within each label record.


X Within a Declarative Section there must be no reference to any
X non-declarative procedure. Conversely, in the non-declarative portion
X there must be no reference to procedure-names that appear in the
X Declarative Section, except that the PERFORM statement can refer to a USE
X procedure, or to procedures associated with it.


X The exit from a Declarative Section is inserted by the compiler following
X the last statement in the section. All logical program paths within the
X section must lead to the exit point.


X There is one exception: A special exit can be specified by the statement
X GO TO MORE-LABELS. When an exit is made from a Declarative Section by
X means of this statement, the system will do one of the following:

  1. X Write the current beginning or ending label and then reenter the USE
    X section at its beginning for further creating of labels. After
    X creating the last label, the user must exit by executing the last
    X statement of the section.
    
    
  2. X Read an additional beginning or ending label, and then reenter the USE
    X section at its beginning for further checking of labels. When
    X processing user labels, the section will be reentered only if there is
    X another user label to check. Hence, there need not be a program path
    X that flows through the last statement in the section.
    
    


X If a GO TO MORE-LABELS statement is not executed for a user label, the
X declarative section is not reentered to check or create any immediately
X succeeding user labels.

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