gtpi1m2lSystem Installation Support Reference

User Trace Area Initialization

User exit routine UCCCEXP is invoked by the C function trace exception routine (CTR0). The C user can use UCCCEXP to initialize storage after the user trace area storage is allocated. The SETTC macro must have been previously issued by this ECB to allocate the C function trace user area (for example, in the CDEB user exit).

General Conditions at Entry

The registers at entry to UCCCEXP 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

SeeUser Exit Routines - Common Programming Considerations.

You can issue the ENATC macro from the CEXP user exit. However, the ENATC macro uses 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 ENATC macro from the CEXP user exit, establish addressability using a base register other than 15.

Note:
You cannot issue the SETTC macro while processing the CEXP user exit routine because the trace table environment has already been set up.

Programming Considerations on Return

See User Exit Routines - Common Return Conditions.

General Conditions on Return

See User Exit Routines - Common Return Conditions.