Storage return

An application uses the IVTCSM REQUEST=FREE_BUFFER macroinstruction to release buffers back to CSM.

CSM returns the buffers to the original requester if all of the following conditions exist:

The original requester specified a buffer return exit address on the FREERTN parameter of the IVTCSM REQUEST=GET_BUFFER macroinstruction.
The original requester is active at the time the IVTCSM REQUEST=FREE_BUFFER macroinstruction is issued.
The application issuing IVTCSM REQUEST=FREE_BUFFER does not specify FREETO=CSM. This parameter is intended for situations where the original requester needs to return buffers without invoking its own buffer return exit.

Optionally, the requester can specify that the buffer is to be cleared when issuing the FREE_BUFFER request. See Clearing data from buffers for more information.

Requirement: All storage manager GET_BUFFER and ASSIGN_BUFFER requests must have a corresponding FREE_BUFFER request before the buffer is considered available for reallocation by CSM or before a buffer return exit is invoked for a buffer obtained specifying a user free routine. This ensures that all users have finished using the buffer.