BEGIN 
          IDENT  BEGIN
          ENTRY  BEGIN
          SYSCOM B1 
          TITLE  BEGIN - TRANSFER PRIMARY COMMUNICATION BLOCK.
*COMMENT  BEGIN - TRANSFER PRIMARY C.B. 
          COMMENT  COPYRIGHT CONTROL DATA SYSTEMS INC.  1992. 
          SPACE  4
*****     BEGIN - TRANSFER PRIMARY COMMUNICATION BLOCK. 
* 
*         W.E. MARTIN.       79/03/30.
          SPACE  4
*         COMMOM TEXT.
  
  
*CALL     COMCMAC 
*CALL     COMKMAC 
*CALL     COMSPRD 
 BEGIN    SPACE  4,30 
***       BEGIN - TRANSFER PRIMARY COMMUNICATION BLOCK. 
* 
*         *BEGIN* ALLOWS A TASK TO SPECIFY THE FWA OF IT-S
*         COMMUNICATION BLOCK AREA AND REBY FREE THE RESTRICTION ON THE 
*         THE IMPLEMENTATION LANGUAGE TO RESERVE THE FIRST WORD ADDRESS 
*         OF THE LOAD FOR THE TRANSACTION EXECUTIVE.  DUE TO THE EXTRA
*         OVERHEAD INCURRED WHEN THIS OPERATION IS EXECUTED, BEGIN
*         IS NOT SUGGESTED FOR GENERAL USE EXCEPT IN THOSE CASES
*         WHERE IT MUST BE USED TO ALLOW A PROGRAMMING LANGUAGE TO
*         INTERFACE TO THE TRANSACTION SUB-SYSTEM.  ALSO, THE *BEGIN* 
*         FUNCTION MUST BE ISSUED AFTER EACH *CALLRTN* IN ORDER 
*         TO OBTAIN THE RESULTS OF THE CALLED TASK. 
* 
*         CALL FORMAT - 
* 
*         FORTRAN EXTENDED - CALL BEGIN ( ADDR )
* 
*         COBOL - ENTER BEGIN USING ADDR. 
* 
*         WHERE - ADDR = FIRST WORD ARDDRESS OF AN ARRAY OR DATA ITEM 
*                        TO WHICH THE PRIMARY TERMINAL COMMUNICATION
*                        BLOCK IS TO BE DELIVERED.
* 
* 
*         USES   A - 1, 2, 6. 
*                X - 0, 1, 2, 6.
*                B - 1. 
* 
*         MACROS ARGERR, BEGIN. 
  
  
          VFD    42/0LBEGIN,18/BEGIN
  
 BEGIN    SUBR               ENTRY/EXIT 
          SB1    1
          ZR     X1,BGN1     IF NO ARGUMENTS - ABORT TASK 
          SX1    X1 
  
*         ISSUE BEGIN REQUEST.
  
          BEGIN  X1 
          EQ     BEGINX      RETURN 
  
*         PROCESS ARGUMENT ERROR. 
  
 BGN1     SA1    BEGIN       READ CALLING ADDRESS 
          MX0    30 
          LX1    30 
          SA2    X1-1        READ CALLING LINE NUMBER 
          BX6    -X0*X2 
          SA6    BGNA 
          ARGERR A6          EXIT TO EXECUTIVE
  
 BGNA     BSS    1           STORAGE FOR ARGERR PARAMETER 
          SPACE  4
          END 
