gtpi1m2hSystem Installation Support Reference

Trace Environment Customization

User exit routine UCCCDEB is invoked by the C function trace exception routine (CTR0). The ISO-C user can use UCCCDEB to customize the C function trace environment.

General Conditions at Entry

The registers at entry to UCCCDEB are:

R2
TCA address

R3
Current DSA address

R5
CID address

R8
Current DLM address

R9
ECB pointer

R11-R15
See User Exit Routines - Common Entry Conditions.

System Conditions at Entry

System state
Supervisor state

System mask
Masked for I/O interrupts

Protect key
0

Address space
EVM.

Programming Considerations at Entry

See User Exit Routines - Common Programming Considerations.

You can issue the SETTC macro or the ENATC macro from the CDEB user exit. However, the SETTC and ENATC macros use register 15 to provide return code information. This use of register 15 conflicts with the user exit usage of register 15 for addressing. Therefore, before you issue the SETTC macro or the ENATC macro from the CDEB user exit, establish addressability using a base register other than 15.

Programming Considerations on Return

See User Exit Routines - Common Return Conditions.

General Conditions on Return

See User Exit Routines - Common Return Conditions.