On Sun, 29 Nov 2015 05:26:26 -0600, Elardus Engelbrecht wrote: > >>Long ago I dealt with this problem in Assembler. I left LRECL=0 in the DCB. >>It would be merged in from either the DSCB or JCL, JCL dominating. I took the >>DCB OPEN exit. If the value was still 0, unavailable from either of those >>sources, I supplied a default LRECL; likewise for BLKSIZE and RECFM. >>Nowadays, SDB gets control last and supplies its default. > >Good approach, but I prefer to a$$ume that LRECL is fixed and known and then >let the system abend the job if an incorrect LRECL is used. But then it is >just me. > I will take little credit/responsibility; I was a novice and had intense mentoring.
It was in a runtime library for a FOSS (almost; there were some amusing license clauses) Pascal system. Many HLLs have similar behaviors. Rexx, for example supplies default but not overriding values of RECFM and LRECL. It used to supply a default BLKSIZE but that was changed by APAR to allow SDB to operate. That actually broke some code (mine and others') because the oldest SDB sometimes chose a BLKSIZE incompatible with explicitly coded LRECL. That also was fixed by APAR, but IBM support recommended that I *always* code BLKSIZE -- an ironic consequence of the introduction of SDB. Many IBM utilities not only supply defaults but even override explicitly coded values of DCB attributes, especially for SYSIN and SYSPRINT. I once had a RECFM=VB PDS corrupted when a user allocated an assembler SYSPRINT to one of its members. I changed it back, recovering most of the members and leaving it broken for the offender. >>If RECFM=V* you may reasonably override to a larger value of LRECL; > (Unless a client QSAM program has a fixed buffer size coded.) >Including VBS (spanned records) too? > I'd hesitate to change anything else to RECFM=32768 (LRECL=X). Rexx lately accommodates VBS but not 32768. > >>if RECFM=F* it's inadvisable to try to change LRECL. > >Yup. You get some nice abends for that change. Easy to fix all values to an >expected LRECL value, but it depends on what you as programmer expects. > Particularly writing to a PDS or MOD to a PS. >Note: DFSORT has some clever magic tricks to figure out the LRECL, RECFM, >DSORG of input data.... I wish I can see how that is done... > Frequently, any submission to this forum that mentions DFSORT or ICETOOL elicits a very expert followupl -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
