&SYSNDX can be used any way you use any other variable. The difference is that
it is incremented with every macro call. It gives you a way to create something
unique for that specific call to a macro. The typical use is as some sort of
branch label within a macro so that multiple uses of the same macro within a
program each have unique branch labels.
MACRO ,
JUNK ,
WTO 'MESSAGE&SYSNDX'
MEND ,
JUNK ,
JUNK ,
JUNK ,
So in this case, each WTO will have a unique message. This may not be useful but
it demonstrates that you are only limited to your imagination on how to use it.
