From: james.harris.1@gmail.com   
      
   On 21/08/2021 09:47, Joe Monk wrote:   
   >   
   >> A nitpick, perhaps, but I think a DSECT is a dummy section, not a data   
   >> section. IIRC a DSECT only becomes relevant when the assembler is told   
   >> to use it to define offsets from a base register.   
   >>   
   >   
   > A DSECT can only contain DS operands ... no code. That is why, in the   
   mainframe world, although you are correct they are named dummy sections, we   
   call them data sections.   
      
   OK.   
      
   >   
   > It does not become addressable within the storage of a program until   
   referenced by a USING statement.   
   >   
   > Common uses include describing the contents of records in files, and or   
   working storage areas. For instance, you may use a DSECT to describe the   
   layout of a punched card, read the punched card, and the MVC the read buffer   
   into a DSECT which describes    
   the fields in more detail so you can reference them.   
      
   Rather than copy the contents, could you also 'get locate' the address   
   of the card's contents into a register and then use the DSECT's   
   structure to access the fields of the card via that register?   
      
   >   
   > I think in my career as a mainframe programmer, i've used DSECTs less than   
   20 times in 30+ years.   
      
   That's surprising. My mainframe experience was much more limited and so   
   long ago that I cannot remember the details but I remember DSECTS   
   reasonably clearly, I think. Besides, I'd have thought that using a   
   template to define storage was a frequent operation.   
      
      
   --   
   James Harris   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)