shutdown (BPX1SHT, BPX4SHT) — Shut down all or part of a duplex socket connection
Function
The shutdown callable service shuts down all or part of a duplex socket connection.
Requirements
Operation | Environment |
---|---|
Authorization: | Supervisor state or problem state, any PSW key |
Dispatchable unit mode: | Task or SRB |
Cross memory mode: | PASN = HASN |
AMODE (BPX1SHT): | 31-bit task or SRB mode |
AMODE (BPX4SHT): | 64-bit task mode only |
ASC mode: | Primary mode |
Interrupt status: | Enabled for interrupts |
Locks: | Unlocked |
Control parameters: | All parameters must be addressable by the caller and in the primary address space. |
Format
The syntax format is as follows:
|
AMODE 64 callers use BPX4SHT with the same parameters.
Parameters
- Socket_descriptor
- Supplied parameter
- Type:
- Integer
- Length:
- Fullword
The name of a fullword that contains the socket file descriptor for which the shutdown is to be done.
- How
- Supplied parameter
- Type:
- Integer
- Length:
- Fullword
The name of a field that contains the condition of the shutdown:- 0 ends communication from Socket (Read).
- 1 ends communication to Socket (Write).
- 2 ends communication both to and from Socket.
- Return_value
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
The name of a fullword in which the shutdown service returns one of the following:- 0 if the request is successful.
- -1 if the request is not successful.
- Return_code
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
The name of a fullword in which the shutdown service stores the return code. The shutdown service returns Return_code only if Return_value is -1. See z/OS UNIX System Services Messages and Codes for a complete list of possible return code values. The shutdown service can return one of the following values in the Return_code parameter:Return_code Explanation EBADF An incorrect file descriptor was supplied. The following reason codes can accompany the return code: JRFileDesNotInUse, JRFileNotOpen. EINVAL The How parameter is incorrect. It is not 0, 1, or 2. The following reason code can accompany the return code: JRBadEntryCode. ENOBUFS A buffer could not be obtained. The following reason code can accompany the return code: JROutofSocketCells. ENOTSOCK Socket_descriptor does not refer to a valid socket descriptor. The following reason code can accompany the return code: JRMustBeSocket. - Reason_code
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
The name of a fullword in which the shutdown service stores the reason code. The shutdown service returns Reason_code only if Return_value is -1. Reason_code further qualifies the Return_code value. For the reason codes, see z/OS UNIX System Services Messages and Codes.
Usage notes
- See Callable services available to SRB mode routines for more information about programming considerations for SRB mode.
- A shutdown for read means that future write operations from the other end of this socket are rejected. Any data that was already written before the shutdown occurred are available for the application that issued the shutdown to read. The data is read until a read is done that returns zero bytes, indicating that there is no more data for that socket.
- A shutdown for write means that any future writes by the application that issued the shutdown request are rejected.
- Regardless of the How option specified, reads are not rejected.
Characteristics and restrictions
There are no restrictions on the use of the shutdown service.
Examples
For an example using this callable service, see BPX1SHT (shutdown) example.