X Left free for the user

No routine in the Library assumes that it will find anything on an X card, so the user is free to put any information he wishes there. To read and interpret information from a set of X cards, see the specifications of:

SUBROUTINE CARDIN read requested card, A80, to COMMON /SCRACH/
SUBROUTINE RDINTG read integer
SUBROUTINE RDREAL read real number
SUBROUTINE RDWORD read word
SUBROUTINE RDWRDS read all remaining words on a card
SUBROUTINE RDNUMS read all remaining numbers on a card.

In the COMMON /CARDRC/ INREAD(24) holds the position in the temporary file (unit IO10) at which X cards start, if there are any, and ICDNO(24) holds the number of X cards read by PREFIN.

So, having declared COMMON /CARDRC/ and COMMON /SCRACH/ at the start, the sequence:

      N=ICDNO(24)
      IF (N .GT. 0) THEN
      ID=INREAD(24)
      DO 1 I=1,N
      CALL CARDIN(ID)
      ID=ID+NYZ
      ........

a piece of code to extract your information off the card

      ........
   1  CONTINUE
      ENDIF

etc

will read and interpret a set of X cards.

If the user wants to use X cards for more elaborate input, in the same way, for example, as L or M cards, he could use FUNCTION ONCARD which looks for an X card with a given CCSL-word, or SUBROUTINE FINDCD which will read the next X card with a given CCSL-word.

NOTE:

The instruction ID=ID+NYZ rather than ID=ID+1 is needed to skip over any Y or Z cards which may be interleaved with the X cards.