HLASM Language Reference

&SYSADATA_DSN System Variable Symbol
| 1 macro
| 2 getlocalsys
| 3 . Define globals for values of interest
| 4 Gblc &clock,&location,&dsname,&nest
| 5 Gbla &nesta
| 6 . now update the globals from within the macro
| 7 &clock setc '&sysclock'
| 8 &location setc '&sysloc'
| 9 &dsname setc '&sysin_dsn'
| 1 &nest setc '&sysnest'
| 11 &nesta seta &sysnest
| 12 mend
| 2 14 r csect
| 15
| 16 define globals in opencode
| 17
| 18 Gblc &clock,&location,&dsname,&nest
| 19 Gbla &nesta
| 2
| 21 invoke macro to update the global values
| 22
| 23 getlocalsys
| 24
| 25 now use the updated values
| 26
| 27 dc c'&clock'
| F2FFF46FF66 + dc c'24-6-11 17:48:42.914829'
| 28 dc c'&nest'
| 1A F1 + dc c'1'
| 29 dc f'&nesta'
| 1B
| 1C 1 + dc f'1'
| 31 end r
Figure 65. Exposing the Value of a Local Scope Variable to Open Code
Uses, Values and Properties: System variable symbols have many uses,
including:
Helping to control conditional assemblies
Capturing environmental data for inclusion in the generated object code
Providing program debugging data
Refer to Appendix C, “Macro and Conditional Assembly Language Summary” on
page 409 for a summary of the values and properties that can be assigned to
system variable symbols.
&SYSADATA_DSN System Variable Symbol
Use &SYSADATA_DSN in a macro definition to obtain the name of the data set to
which the assembler is writing the associated data.
The local-scope system variable symbol &SYSADATA_DSN is assigned a
read-only value each time a macro definition is called.
When the assembler runs on the MVS operating systems, the value of
the character string assigned to &SYSADATA_DSN is always the value stored in
the JFCB for SYSADATA. If SYSADATA is allocated to DUMMY, or a NULLFILE,
the value in &SYSADATA_DSN is NULLFILE.
For example, &SYSADATA_DSN might be assigned a value such as:
IBMAPC.SYSADATA
Chapter 7. How to Specify Macro Definitions 263