If you have an A-con in a DSECT (with an EXTRN) that will cause you difficulty in many cases because it will put the reference into your external symbol dictionary (and thus require you to resolve it at bind time unless you like non-0 return codes). That is not the case for a V-con.
That is why you'll see in macros such as the CVT that when we need to use an A-con to get a pointer-defined address of a routine when expanded as a CSECT (which we expect only our instantiation module that is in IEANUC01 does), there is macro logic so that the expansion for the DSECT does not do that. Look for 80000000 in the CVT and you will find many examples. Peter Relson z/OS Core Technology Design
