I am not 100% certain this is the right Forum for this post but everything I am going to talk about is written in Assembler Language and I didn't see an MVS Advanced Topics Forum, which is where I would have placed it if such a Forum existed.
Anyway what I am doing is using the Subsystem Interface in an External Writer program and specifically function code 79 (Subsystem Application Programming Interface or SAPI). Using that function code there is a bit you can set that will return to you SWB information about the SYSOUT file you are interested in. I have successfully turned on that bit and gotten the return code that tells me that the SWB information was successfully retrieved. Unfortunately what I am having trouble with is retrieving that information from the system at that point.
The documentation tells you to use either the SJFREQ macro or the SWBTUREQ macro to retrieve the information in dynamic allocation style text units. I have not been able to get either of those macros to work. The one that I have spent the most time on is the SWBTUREQ macro because there is a partial example in the documentation and I was able to get a return code of zero using that example. But when I look at the output text units that I retrieved they are all just blank characters. The SYSOUT attributes I am trying to retrieve are BUILDING, DEPT, and ROOM and when I look in SDSF at the SYSOUT file it clearly shows that those attributes are not blank, but for some reason that I don't understand the SWBTUREQ macro returns only blanks.
If anybody out there has worked with this stuff and can help me I would greatly appreciate it.