The tcsendbreak callable service sends a BREAK signal to a terminal that uses asynchronous serial data transmission.
If the target terminal is an OCS-attached serial terminal, the BREAK signal is sent to the terminal. If the target terminal is a pseudoterminal (pty), control returns without any significant action.
Operation | Environment |
---|---|
Authorization: | Supervisor or problem state, any PSW key |
Dispatchable unit mode: | Task |
Cross memory mode: | PASN = HASN |
AMODE (BPX1TSB): | 31-bit |
AMODE (BPX4TSB): | 64-bit |
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. |
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AMODE 64 callers use BPX4TSB with the same parameters.
The name of a fullword that contains the file descriptor for the terminal device to which the break is to be sent.
The name of a fullword that contains the duration of the BREAK transmission. If the target terminal is a pseudoterminal, the Duration parameter has no effect.
The name of a fullword in which the tcsendbreak service returns 0 if the request is successful, or -1 if it is not successful.
Return_code | Explanation |
---|---|
EBADF | File_descriptor is not a valid open file descriptor. |
EINTR | The tcsendbreak (BPX1TSB, BPX4TSB) service was called from a background job, and the SIGTTOU signal either had default action or a signal handler. The function was not performed. |
EIO | The process group of the process that is issuing the function is an orphaned, background process group, and the process that is issuing the function is not ignoring or blocking SIGTTOU. |
ENOTTY | File_descriptor is not associated with a terminal. |
The name of a fullword in which the tcsendbreak service stores the reason code. The tcsendbreak 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.
The following table defines the processing of the SIGTTOU signal when tcsendbreak is called from a background process against a controlling terminal:
SIGTTOU processing | Expected behavior |
---|---|
Default or signal handler | The SIGTTOU signal is generated. |
Ignored or blocked | The SIGTTOU signal is not sent. |
There are no restrictions on the use of the tcsendbreak service.
For an example using this callable service, see BPX1TSB (tcsendbreak) example.