> -----Original Message----- > From: IBM Mainframe Assembler List > [mailto:[email protected]] On Behalf Of Paul Gilmartin > Sent: Wednesday, February 22, 2012 8:47 AM > To: [email protected] > Subject: Re: FLOWASM observation > > On Feb 21, 2012, at 12:07, Edward Jaffe wrote: > > .... > > I believe this change will instruct the assembler to fall > back to its own > > internal OPEN and READ processing for SYSIN (or whatever DD > you're using) which, > > as you know, contains support for z/OS UNIX files. > > > Why is a RDJFCB required at all? I'm primarily not an assembler > programmer, but I've coded a few OPENs successfully, but never > a RDJFCB. I would suggest that if RDJFCB fails, let FLOWASM, > not assembler, proceed with its OPEN and I/O processing. > > In my understanding, the statement that "the assembler ... contains > support for z/OS UNIX files" is misleading. The bulk of such > support lies in the access method. IIRC, even before HLASM > announced support for z/OS UNIX files, I was able to ALLOCATE > SYSIN to a UNIX file and assemble it successfully.
The support for UNIX files in the assembler seems primitive. Basically, it appears that all that is done is printing the UNIX file name allocated to "SYSIN" in the SYSPRINT listing. Which is why FLOWASM does the RDJFCB. When you override the assembler's input with your own SOURCE exit, the assembler doesn't know where you're getting the input from. And so your routine can pass that information back to the assembler to include it in the SYSPRINT listing. Which FLOWASM does by using the RDJFCB. I put in a small change so that if the RDJFCB passes back a DSN of CL44'...PATH.SPECIFIED...', then the OPEN subprocess tells the assembler to use it's standard input source, but still send each record read by the assembler to the PROCESS subfunction in order to "do its magic". It works wonderfully. I've also changed the PROCESS subfunction to translate all x'05' (EBCDIC tabs) to x'40' (a single space). That's because I sometimes use vi to edit my assembler. I forget myself and use the ! tab key. > > I had such a discussion a while back on IBM-MAIN where one > contributor rebutted, asserting that using information in the > JCFB, DSCB, UCB, etc. he was able to significantly optimize > performance. If so, fine, but if the fancy stuff fails, he > should fall back to good old OPEN, GET/PUT, CLOSE which will > provide satisfatory operation for a greater number of users. > > But certainly I appreciate your generosity with the tools > that you author. > > -- gil -- John McKown Systems Engineer IV IT Administrative Services Group HealthMarkets(r) 9151 Boulevard 26 * N. Richland Hills * TX 76010 (817) 255-3225 phone * [email protected] * www.HealthMarkets.com Confidentiality Notice: This e-mail message may contain confidential or proprietary information. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. HealthMarkets(r) is the brand name for products underwritten and issued by the insurance subsidiaries of HealthMarkets, Inc. -The Chesapeake Life Insurance Company(r), Mid-West National Life Insurance Company of TennesseeSM and The MEGA Life and Health Insurance Company.SM
