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QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running the QNX OS 8.0.
Utilities & Libraries
Devctl and Ioctl Commands
DCMD_CHR_*
DCMD_CHR_TCSETATTR, DCMD_CHR_TCSETATTRD, DCMD_CHR_TCSETATTRF
Set terminal properties

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This User's Guide describes version 8.0 of the Integrated Development Environment (IDE) that's part of the QNX Tool Suite.
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QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running the QNX OS 8.0.
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  - Devctl and Ioctl Commands
    - BIOC*
    - CAN_DEVCTL_*
    - DCMD_ALL_*
    - DCMD_BLK_*
    - DCMD_CAM_*
    - DCMD_CHR_*
      - DCMD_CHR_DISABLE_LOGGING
        Disable the logging of transmitted and/or received data
      - DCMD_CHR_ENABLE_LOGGING
        Enable the logging of transmitted and/or received data
      - DCMD_CHR_FLUSH_LOG
        Force a flush of the logged data to the log files
      - DCMD_CHR_FORCE_RTS
        Force the RTS line to the specified level
      - DCMD_CHR_GETOBAND
        Get out-of-band data stored by a device
      - DCMD_CHR_GETOBAND_EXTENDED
        Get extended out-of-band data stored by a device
      - DCMD_CHR_GETSIZE
        Get the size of a character device
      - DCMD_CHR_GETVERBOSITY
        Get the verbosity of io-char
      - DCMD_CHR_IDLE
        Put the device into idle
      - DCMD_CHR_ISATTY
        Test to see if a file descriptor is associated with a terminal
      - DCMD_CHR_ISCHARS
        Determine the number of characters waiting to be read
      - DCMD_CHR_ISSIZE
        Determine the size of the device's input buffer
      - DCMD_CHR_LINESTATUS
        Get line status information for the terminal device
      - DCMD_CHR_OSCHARS
        Determine the number of characters waiting to be sent
      - DCMD_CHR_OSSIZE
        Determine the size of the device's output buffer
      - DCMD_CHR_PARCTL
        Control a parallel device
      - DCMD_CHR_PNPTEXT
        Get the text associated with a plug and play device
      - DCMD_CHR_PUTOBAND
        Send out of band data to the device
      - DCMD_CHR_RESET
        Reset the device
      - DCMD_CHR_RESUME
        Make the device resume from idle
      - DCMD_CHR_SERCTL
        Control serial communication lines
      - DCMD_CHR_SET_LOGGING_DIR
        Set the path to the logging directory
      - DCMD_CHR_SETSIZE
        Set the size of a character device
      - DCMD_CHR_SETVERBOSITY
        Set the verbosity of io-char
      - DCMD_CHR_TCDRAIN
        Wait until all output has been transmitted to a device
      - DCMD_CHR_TCFLOW
        Perform a flow-control operation on a data stream
      - DCMD_CHR_TCFLUSH
        Flush the input or output stream
      - DCMD_CHR_TCGETATTR
        Get the terminal properties
      - DCMD_CHR_TCGETPGRP
        Get the process group ID associated with a device
      - DCMD_CHR_TCGETSID
        Get the process group ID of a controlling terminal's session leader
      - DCMD_CHR_TCINJECTC, DCMD_CHR_TCINJECTR
        Inject characters into a device's input buffer
      - DCMD_CHR_TCSETATTR, DCMD_CHR_TCSETATTRD, DCMD_CHR_TCSETATTRF
        Set terminal properties
      - DCMD_CHR_TCSETPGRP
        Set the process group ID associated with a device
      - DCMD_CHR_TCSETSID
        Set the process group ID of a controlling terminal's session leader
      - DCMD_CHR_TTYINFO
        Get information about a terminal device
      - DCMD_CHR_WAITINFO
        Get information about blocked processes
    - DCMD_DUMPER_*
    - DCMD_F3S_*
    - DCMD_FSYS_*
    - DCMD_IP_*
    - DCMD_MEMMGR_*
    - DCMD_MISC_*
    - DCMD_MMCSD_*
    - DCMD_PROC_*
    - DCMD_PROF_*
    - DCMD_PTPD_*
    - DCMD_SDIO_*
    - DCMD_SDMMC_*
    - DCMD_SPI_*
    - PTP_*
    - FIO*
    - TC*
    - TIOC*
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Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation, explains how to obtain technical support, and provides some information about licensing.

DCMD_CHR_TCSETATTR, DCMD_CHR_TCSETATTRD, DCMD_CHR_TCSETATTRF

QNX SDP8.0Devctl and Ioctl CommandsDeveloper

Set terminal properties

Synopsis:

#include <sys/dcmd_chr.h>

#define DCMD_CHR_TCSETATTR    __DIOT(_CMD_IOCTL_TTY, 20, struct termios)  /* TIOCSETA */
#define DCMD_CHR_TCSETATTRD   __DIOT(_CMD_IOCTL_TTY, 21, struct termios)  /* TIOCSETAW */
#define DCMD_CHR_TCSETATTRF   __DIOT(_CMD_IOCTL_TTY, 22, struct termios)  /* TIOCSETAF */

Arguments to devctl():


Argument	Value
`filedes`	A file descriptor that you obtained by opening the device.
`dcmd`	DCMD_CHR_TCSETATTR, DCMD_CHR_TCSETATTRD, or DCMD_CHR_TCSETATTRF
`dev_data_ptr`	A pointer to a struct termios
`n_bytes`	`sizeof(struct termios)`
`dev_info_ptr`	NULL

Description:

These commands change the current terminal control settings of a device:

DCMD_CHR_TCSETATTR — make the change immediately
DCMD_CHR_TCSETATTRD — don't make the change until all currently written data has been transmitted.
DCMD_CHR_TCSETATTRF — don't make the change until all currently written data has been transmitted, at which point any received but unread data is also discarded.

They're also implemented as devctl() commands:


devctl() command	ioctl() command
DCMD_CHR_TCSETATTR	TIOCSETA
DCMD_CHR_TCSETATTRD	TIOCSETAW
DCMD_CHR_TCSETATTRF	TIOCSETAF

Note:

These commands are for internal use, and you shouldn't use them directly. Instead use the tcsetattr() cover function.

Input:

A termios structure.

Output:

None.

See also:

DCMD_CHR_TCGETATTR, TIOCSETA, TIOCSETAF, TIOCSETAW

devctl(), tcsetattr(), termios in the QNX OS C Library Reference

Page updated: August 11, 2025