gtpi1m1iSystem Installation Support Reference

Get Common Block

User exit routine UCCGCB is invoked by the Get Common Block routine after a common block has been allocated and before returning to the caller. This exit point, named GCB, can be activated dynamically. Exit point GCB is in copy segment CLHV of CSECT CCSTOR.

General Conditions at Entry

The registers at entry to UCCGCB are:

R1
CCT (Common Block Control Table) entry pointer.

R2
SVM address of the common block.

R3
Address of routine invoking CL$GCOMC.

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

System Conditions at Entry

System state
Supervisor

System mask
Masked for I/O interrupts

Protect key
0

Address Space
SVM or EVM.

Programming Considerations at Entry

  1. No core block management data records can be modified.
  2. The exit point can be invoked in either the SVM or the EVM. Because the block address is common to both address spaces, an address space flag is not supplied or needed.
  3. See User Exit Routines - Common Programming Considerations for other considerations.

Programming Considerations on Return

See User Exit Routines - Common Return Conditions.

General Conditions on Return

See User Exit Routines - Common Return Conditions.