Possible uses

Some possible uses of the OUTDES exits are described below:

Change the operands that the user specifies on the command
You can use the initialization exit to change the operands that users specify on the OUTDES command. The initialization exit receives the address of the command buffer. It can change the operands the user specifies on the OUTDES command by using a new command buffer. For example, the initialization exit can scan the command buffer and correct any errors on the command.
Provide installation-defined pseudo-operands
You can provide pseudo-operands for your installation's users that are equivalent to two or more OUTDES operands. Providing pseudo-operands makes it easier for users to issue the OUTDES command. Users need not remember several OUTDES operands. They can specify the pseudo-operand.

For example, you could associate a pseudo-operand named OUT1 with four OUTDES operands. The initialization exit can scan the command buffer. If the exit finds the pseudo-operand OUT1, it can replace OUT1 with the actual OUTDES operands and return a new command buffer.

To check the command buffer and change its contents, the initialization exit can:

Scan the command buffer and decide, based on your own criteria, to change the command the user issued
Obtain storage for a new command buffer
Build the new command buffer
Update the key, length, and data fields for the new command buffer as follows:
Key

X'02'

Length

the length of the new command buffer

Data

the address of the new command buffer
Set a return code of 0 and return control to the OUTDES command processor.

The exit must not change the command buffer it receives. It must create a new command buffer and return the address of the new command buffer to OUTDES. For more information about the command buffer and the new command buffer, see TSO/E standard exit parameter list. For information about the format of the command buffer, see Command buffer.

You must also write a termination exit to free the storage the initialization exit obtains for the new command buffer. When the OUTDES command processor invokes the termination exit, it passes the address of the new command buffer to the termination exit. The termination exit frees the storage for the new command buffer.