Call the Latch_Release service to release ownership of an owned latch or a pending request to obtain a latch. Requestors should call Latch_Release when the use of a resource associated with a latch is no longer required. The following callable services are related to Latch_Release:

ISGLCRT

Creates a latch set that an application can use to serialize resources.

ISGLOBT

Requests exclusive or shared control of a latch.

ISGLPRG

Purges all granted and pending requests for a particular requestor within a specific latch set.

In the following description of Latch_Release:

• The term requestor describes a program that calls the Latch_Release service to release ownership of an owned latch or a pending request to obtain a latch.
• Constants defined in the latch manager IDFs are followed by their numeric equivalents; you may specify either when coding calls to Latch_Obtain. For example, “ISGLREL_COND (value of 1)” indicates the constant ISGLREL_COND and its associated value, 1.

Assign values to the following parameters:

• latch_set_token
• latch_token
• release_option

Latch_Release returns a value in the following parameter:

• return_code

Latch_Release uses the following parameter for temporary storage:

• work_area

The parameters are explained as follows:

latch_set_token

Specifies an 8-byte area that contains the latch set token returned to the caller of the Latch_Create service. The latch set token identifies the latch set that contains the latch to be released.

,latch_token

Specifies an 8-byte area that contains the latch token returned to the caller of the Latch_Obtain service. The latch token identifies the request to be released.

,release_option

Specifies a fullword integer that tells the latch manager what to do when the requestor either no longer owns the latch to be released or still has a pending request to obtain the latch to be released:

ISGLREL_UNCOND (value of 0)

Abend the requestor:

• If a requestor originally specified an obtain_option of ISGLOBT_SYNC (value of 0) when obtaining the latch, the latch manager does not release the latch. The system abends the caller of Latch_Release with abend X'9C6', reason code xxxx0009.
• If a requestor originally specified an obtain_option of ISGLOBT_ASYNC_ECB (value of 2) when obtaining the latch, the latch manager does not release the latch. The system abends the caller of Latch_Release with abend X'9C6', reason code xxxx0007.
• If the latch manager does not find a previous Latch_Obtain request for the specified latch, the system abends the caller of Latch_Release with abend X'9C6', reason code xxxx000A.

ISGLREL_COND (value of 1)

Return control to the requestor:

• If a requestor originally specified an obtain_option of ISGLOBT_ASYNC_ECB (value of 2) when obtaining the latch, the latch manager releases the request for ownership of the latch. The system returns control to the caller of Latch_Release with a return code of ISGLREL_NOT_OWNED_ECB_REQUEST (value of 4).
• If a requestor originally specified an obtain_option of ISGLOBT_SYNC (value of 0) when obtaining the latch, the latch manager does not release the request for ownership of the latch. The system returns control to the caller of Latch_Release with a return code of ISGLREL_STILL_SUSPENDED (value of 8).
• If the latch manager does not find a previous Latch_Obtain request for the specified latch, the system returns control to the caller of Latch_Release with a return code of ISGLREL_INCORRECT_LATCH_TOKEN (value of 12).

,work_area

Specifies a 256-byte work area that provides temporary storage for the Latch_Release service. The work area should begin on a doubleword boundary to optimize performance. The work area must be in the same storage key as the caller of Latch_Release.

,return_code

Specifies a fullword integer that is to contain the return code from the Latch_Release service.