The OBTAIN option of SETLOCK macro is written as follows:

The parameters are explained as follows:

OBTAIN

Specifies that the lock designated by the TYPE parameter is to be obtained on the caller's behalf.

,TYPE=CPU

,TYPE=CMS

,TYPE=LOCAL

,TYPE=CML,ASCB=(11)

,TYPE=CML,ASCB=addr

Specifies the type of lock. The types available are:

CPU

The processor lock. It is a pseudo spin lock providing MVS-recognized disablement. There is one CPU lock per processor and no processor can request another processor's lock. The lock is always available. Users can obtain the CPU lock to become disabled for I/O and external interrupts.

CMS

The cross memory services lock. It is a global suspend lock used to serialize functions between address spaces.

LOCAL

The lock that serializes resources in the home address space pointed to by PSAAOLD. It is a local level suspend lock.

CML

The cross memory local lock. It is a local level suspend type lock used to serialize resources in an address space other than the home address space.

The requestor of a CML lock must have authority to access the specified address space before requesting the lock. To establish authority, the requestor sets the primary or secondary address space to the one specified by the ASCB=(11) or ASCB=addr parameter. Register 11 or addr must contain the address of the ASCB whose local lock is requested. This address space must be nonswappable before the SETLOCK request.

Note: If the requestor specifies OBTAIN,TYPE=CML and the ASCB parameter points to the home address space, the request is treated as though the LOCAL lock were being obtained.

,MODE=COND

,MODE=UNCOND

Specifies whether the lock is to be conditionally or unconditionally obtained.

COND

Specifies that the lock is to be conditionally obtained. That is, if the lock is not owned on another processor, it is acquired on the caller's behalf. If the lock is already held, control is returned indicating that the caller holds the lock or that another unit of work on another processor owns the lock.

UNCOND

Specifies that the lock is to be unconditionally obtained. That is, if the lock is not owned on another processor, it is acquired on the caller's behalf. If the lock is already held by the caller, control is returned to the calling program indicating that it already owns the lock. If the lock is held on another processor, the system suspends the SETLOCK caller until the lock is available.

The system does not permit an unconditional OBTAIN request for a CML lock if the lock is held by a unit of work that is set nondispatchable.

,REGS=SAVE

,REGS=USE

,REGS=STDSAVE

Specifies the use of general purpose registers by the SETLOCK macro.

SAVE

Specifies that the contents of registers 11 through 14 are saved in the area pointed to by register 13 and are restored upon completion of the SETLOCK request. This save area must be at least 20 bytes, and must not be the same area as the standard linkage save area used by the program.

Upon completion of the SETLOCK macro with REGS=SAVE, the register contents are as follows:

Register

Contents

0-14

Unchanged

15

Return code

USE

Specifies that the contents of registers 11 through 13 are saved in work registers 0, 1, and 15.

Upon completion of the SETLOCK macro with REGS=USE, the register contents are as follows:

Register

Contents

0-1

Used as work registers by the system

2-13

Unchanged

14

Used as a work register by the system

15

Return code

STDSAVE

Specifies that the contents of registers 2 through 12 are saved in a standard 72-byte save area pointed to by register 13.

Upon completion of the SETLOCK macro with REGS=STDSAVE, the register contents are as follows:

Register

Contents

0-1

Unchanged

2-13

Unchanged

14

Used as a work register by the system

15

Return code

Note: See Output register information for information on register usage when the REGS parameter is not specified.

,RELATED=value

Specifies information used to self-document macros by “relating” functions or services to corresponding functions or services. The format and contents of the information specified are at the discretion of the user, and may be any valid coding values.

SETLOCK might abnormally terminate with abend code X'073'. See z/OS MVS System Codes for an explanation and programmer response for this code.

When control returns to the caller, register 15 (or register 13, if the REGS parameter is not specified) contains one of the following hexadecimal return codes:

When the SETLOCK OBTAIN request is for the CPU lock, the system returns only return code 0. You do not need to check the return code because once control is returned to you after the SETLOCK OBTAIN,TYPE=CPU request, you will have the CPU lock.