&SYSNEST System Variable Symbol

Use &SYSNEST to obtain the current macro instruction nesting level.

The local-scope system variable symbol &SYSNEST is assigned a read-only value each time a macro definition is called from a source module.

The value assigned to &SYSNEST is a number from 1 to 99999999. No leading zeros are generated as part of the number. When a macro is called from open code, the value assigned to &SYSNEST is the number 1. Each time a macro definition is called by an inner macro instruction, the value assigned to &SYSNEXT is incremented by 1. Each time an inner macro exits, the value is decremented by 1.

Notes:

The value of the type attribute of &SYSNEST (T'&SYSNEST) is always N.
The value of the count attribute (K'&SYSNEST) is equal to the number of digits assigned.

The following example shows the values assigned to &SYSNEST:

          MACRO
          OUTER
          DC              A(&SYSNEST)         Statement 1
          INNER1                              Statement 2
          INNER2                              Statement 3
          MEND

          MACRO
          INNER1
          DC              A(&SYSNEST)         Statement 4
          INNER2                              Statement 5
          MEND

          MACRO
          INNER2
          DC              A(&SYSNEST)         Statement 6
          MEND
--------------------------------------------------------------------
          OUTER                               Statement 7
+         DC              A(1)
+         DC              A(2)
+         DC              A(3)
+         DC              A(2)

Statement 7 is in open code. It calls the macro OUTER. &SYSNEST is assigned a value of 1 which is substituted in statement 1.

Statement 2, within the macro definition of OUTER, calls macro INNER1. The value assigned to &SYSNEST is incremented by 1. The value 2 is substituted for &SYSNEST in statement 4.

Statement 5, within the macro definition of INNER1, calls macro INNER2. The value assigned to &SYSNEST is incremented by 1. The value 3 is substituted for &SYSNEST in statement 6.

When the macro INNER2 exits, the value assigned to &SYSNEST is decremented by 1. The value of &SYNEST is 2.

When the macro INNER1 exits, the value assigned to &SYSNEST is decremented by 1. The value of &SYSNEST is 1.

Statement 3, within the macro definition of OUTER, calls macro INNER2. The value assigned to &SYSNEST is incremented by 1. The value 2 is substituted for &SYSNEST in statement 6.