CTMCOD Programming Techniques

You can use the following programming techniques when working with the CTMCOD macro:

• You may need to update a certain code in the MIT after reading some other codes. For example, you must update MITCCPRE, the number of code values in an ON statement, after reading and counting all the code values in that block.

  To do this, save CTMBCOD fields CODPREVC, CODPREVL, and CODAMIC after reading the code to be updated, and then restore those values before the code is updated.

  The following sample code illustrates this technique:

CTMCOD GETNEXT,CODE=MITCCPRE

MVC KEEPPREC,CODPREVC

MVC KEEPPREL,CODPREVL

MVC KEEPAMIC,CODAMIC

(read and process other codes)

MVC CODPREVC,KEEPPREC

MVC CODPREVL,KEEPPREL

MVC CODAMIC,KEEPAMIC

CTMCOD PUT

CODPREVC contains the address of the code that was read by CTMCOD GETNEXT. CODPREVL contains the length from this address until end of the MIC. CODAMIC contains the address of the MIC where the code resides. All these fields are used by CTMCOD PUT in order to locate the requested code and replace it with the value in CODOUTC.

• Programs that must read codes starting from a certain code, after other codes have been read and/or added, should also keep (and then restore) the values of fields CODCURRC and CODCURRL after the issuance of CTMCOD GETNEXT. These fields contain the address of the next code to be read after a code has been read, and the length from that address to the end of the MIC.
• When CTMCOD is used in a loop (for example, to go over all the codes of a certain type in a job), and for each loop iteration CTMCOD is used for other purposes, the following fields in CTMBCOD must be saved after the main loop's GETNEXT and restored after the internal CTMCODs:
  • CODPREVC
  • CODCURRC
  • CODPREVL
  • CODCURRL
  • CODAMIC
  • CODFUNC