tcdrain (BPX1TDR, BPX4TDR) — Wait until output has been transmitted

Function

The tcdrain callable service waits until all output sent to a file descriptor has actually been sent to the terminal device.

Requirements

Operation	Environment
Authorization:	Supervisor or problem state, any PSW key
Dispatchable unit mode:	Task
Cross memory mode:	PASN = HASN
AMODE (BPX1TDR):	31-bit
AMODE (BPX4TDR):	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.

Format

The syntax format is as follows:

CALL BPX1TDR,(File_descriptor,
              Return_value,
              Return_code,
              Reason_code)

AMODE 64 callers use BPX4TDR with the same parameters.

Parameters

File_descriptor

Supplied parameter

Type:: Integer
Length:: Fullword

The name of a fullword that contains the file descriptor that represents the output device.

Return_value

Returned parameter

Type:: Integer
Length:: Fullword

The name of a fullword in which the tcdrain service returns 0 if the request is successful, or -1 if it is not successful.

Return_code

Returned parameter

Type:: Integer
Length:: Fullword

The name of a fullword in which the tcdrain service stores the return code. The tcdrain 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 tcdrain service can return one of the following values in the Return_code parameter:

Return_code	Explanation
EBADF	File_descriptor does not describe a valid open file.
EINTR	A signal interrupted the service before all output had been sent.
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.

Reason_code

Returned parameter

Type:: Integer
Length:: Fullword

The name of a fullword in which the tcdrain service stores the reason code. The tcdrain 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

For slave pseudoterminals, data is considered written when the master side has read it.

The following table defines the processing of the SIGTTOU signal when tcdrain is called from a background process against a controlling terminal:

SIGTTOU processing	Expected behavior
Default or signal handler	The SIGTTOU signal is generated. The function is not performed. Return_value is set to -`1`, and Return_code is set to EINTR.
Ignored or blocked	The SIGTTOU signal is not sent. The function continues normally.

tcdrain (BPX1TDR, BPX4TDR) — Wait until output has been transmitted

Function

Requirements

Format

Parameters

Usage notes

Related services

Characteristics and restrictions

Examples