Version_Service

Version_Service returns the highest version of the APPC/MVS callable services that is currently available on the system. Available services are those with a version number that is equal to or between the version number where the service was introduced and the version number returned from the Version_Service.

Example

The following example explains the versioning of APPC/MVS callable services:

Assume that the ATBxxx1 service was introduced in release A (the first release using this versioning scheme). The invocation of ATBxxx1 expects an Unidentify_type and a return code parameter.
In the next release (release B) a new parameter is added to form the ATBxxx2 service. The invocation of the new service expects only a return code parameter.
In the following release (release C), a new parameter is added to the ATBxxx2 service to form the ATBxxx3 service. No changes are made to the ATBxxx1 and ATBxxx2 services.

The following table shows how a call to the Version_Service returns callable service version numbers for the Allocate service:

Table 1. Example Values Returned by the Version_Service
Current Version	Value Returned	Services Available
0 (MVS/ESA SP 4.2.0)	N/A (See note 1)	ATBALLOC
1 (MVS/ESA SP 4.2.2)	1	ATBALLOC
2 (MVS/ESA SP 4.3.0)	2	ATBALLOC, ATBALC2
3 (MVS/ESA SP 5.1.0)	3	ATBALLOC, ATBALC2
4 (OS/390 V1R3)	4 or 5 (See Note 2)	ATBALLOC, ATBALC2, ATBALC5
5 (OS/390 V2R8)	5	ATBALLOC, ATBALC2, ATBALC5
6 (z/OS V1R7)	6	ATBALLOC, ATBALC2, ATBALC5, ATBALC6

Note:

The Version_Service was not available in MVS/ESA SP 4.2.0.
If APAR OW33764 is installed, then the Version_Service will return a value of 5. Otherwise, a value of 4 will be returned.

Requirements

Authorization:

Supervisor state or problem state, any PSW key

Dispatchable unit mode:

Task or SRB mode

Cross memory mode:

Any PASN, any HASN, any SASN

AMODE:

31-bit

ASC mode:

Any

Interrupt status:

Enabled or disabled for I/O and external interrupts

Locks:

The caller may hold locks, but is not required to hold any.

Format

Figure 1. ATBVERS - Callable Service Version Service

CALL ATBVERS(
        Callable_Service_Version_Number,
        Return_Code,
       );

Parameters

Callable_Service_Version_Number

Returned parameter

Type: Integer
Char Set: N/A
Length: 4 bytes

The highest version of all APPC/MVS callable services currently available on the system.

Return_Code

Returned parameter

Type: Integer
Char Set: N/A
Length: 4 bytes

Valid values for this parameter are:

Decimal Value: Description
0: The Version_Service successfully returned the version number.
48: A service failure occurred.

Restrictions

Transaction programs that call Version_Service while in task mode should not have any enabled unlocked task (EUT) functional recovery routines (FRRs) established. For more information about EUT FRRs, see the section on providing recovery in z/OS MVS Programming: Authorized Assembler Services Guide.