Change User Space Attributes (QUSCUSAT) API

The Change User Space Attributes (QUSCUSAT) API changes the attributes of a user space object. This API can be used to:

• Extend or truncate a user space
• Mark or unmark the user space as automatically extendible by the system
• Change the initial value to which future extensions of the user space will be set
• Change the number of pages transferred between main storage and auxiliary storage

Authorities and Locks

Library Authority

*EXECUTE

User Space Authority

*CHANGE, *OBJMGT

User Space Lock

*EXCL

Required Parameter Group

Returned library name

OUTPUT; CHAR(10)

The name of the library that contains the changed user space object. If the space attributes are successfully changed, the name of the library in which the user space was found is returned.

Qualified user space name

INPUT; CHAR(20)

The first 10 characters contain the user space name, and the second 10 characters contain the name of the library where the user space is located. The special values supported for the library name are *LIBL and *CURLIB.

Attributes to change

INPUT; CHAR(*)

The attributes of the user space object that you want to change.

The information must be in the following format:

Number of variable length records	BINARY(4) The total number of all of the variable length records.
Variable length records	The attributes of the user space to change and the data used for the change. For the specific format of the variable length record, refer to Format for Variable Length Records.

Error code

I/O; CHAR(*)

The structure in which to return error information. For the format of the structure, see Error Code Parameter.

Format for Variable Length Records

If you specify a length of data that is longer than the key field's defined data length, the data will be truncated at the right. No error message will be returned.

If you specify a length of data that is shorter than the key field's defined data length, an error message will be returned.

You may specify a key more than once. If duplicate keys are specified, the last specified value for that key is used.

Each variable length record must be 4-byte aligned. If not, unpredictable results may occur.

Field Descriptions

Data. The value to which a specific user space attribute is to be changed. All values are validity checked.

Key. The user space attribute to be changed. Only specific attributes can be changed. Refer to Keys for more information.

Length of data. The length of the new user space attribute value. The length of data field is used to get addressability to the next attribute record.

Keys

The following table lists the keys that can be used in the attribute record.

Field Descriptions

Automatic extendibility. Whether or not the user space is automatically extended by the system when the end of the space is encountered.

Initial value. The initial value to which future extensions of the user space will be set. You will achieve the best performance if you set this byte to hexadecimal zeros (X'00').

Space size. The size in bytes of the user space object. If this value is smaller than the current size of the space, the user space is truncated. If it is larger, the space is extended.

Transfer size request. The number of pages to be transferred between main storage and auxiliary storage. This is only a request, as the machine may use a value of its choice in some circumstances. Allowable values range between 0 and 32 pages. A value of 0 is an indication that the machine should use the default transfer size for the user space. A larger transfer size may allow for better performance of applications processing the user space.

Error Messages