TIOCMSET(2const) - Linux manual page (original) (raw)

TIOCMSET(2const) TIOCMSET(2const)

NAME top

   TIOCMGET, TIOCMSET, TIOCMBIC, TIOCMBIS, TIOCMIWAIT, TIOCGICOUNT -
   modem control

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <asm/termbits.h>** /* Definition of **TIOC*** constants */
   **#include <sys/ioctl.h>**

   **int ioctl(int** _fd_**, TIOCMGET, int ***_argp_**);**
   **int ioctl(int** _fd_**, TIOCMSET, const int ***_argp_**);**
   **int ioctl(int** _fd_**, TIOCMBIC, const int ***_argp_**);**
   **int ioctl(int** _fd_**, TIOCMBIS, const int ***_argp_**);**
   **int ioctl(int** _fd_**, TIOCMIWAIT, int** _arg_**);**
   **int ioctl(int** _fd_**, TIOCGICOUNT, struct serial_icounter_struct ***_argp_**);**

   **#include <linux/serial.h>**

   **struct serial_icounter_struct;**

DESCRIPTION top

   **TIOCMGET**
          Get the status of modem bits.

   **TIOCMSET**
          Set the status of modem bits.

   **TIOCMBIC**
          Clear the indicated modem bits.

   **TIOCMBIS**
          Set the indicated modem bits.

   The following bits are used by the above ioctls:

   **TIOCM_LE** DSR (data set ready/line enable)
   **TIOCM_DTR** DTR (data terminal ready)
   **TIOCM_RTS** RTS (request to send)
   **TIOCM_ST** Secondary TXD (transmit)
   **TIOCM_SR** Secondary RXD (receive)
   **TIOCM_CTS** CTS (clear to send)
   **TIOCM_CAR** DCD (data carrier detect)
   **TIOCM_CD** see TIOCM_CAR
   **TIOCM_RNG** RNG (ring)
   **TIOCM_RI** see TIOCM_RNG
   **TIOCM_DSR** DSR (data set ready)

   **TIOCMIWAIT**
          Wait for any of the 4 modem bits (DCD, RI, DSR, CTS) to
          change.  The bits of interest are specified as a bit mask
          in _arg_, by ORing together any of the bit values, **TIOCM_RNG**,
          **TIOCM_DSR**, **TIOCM_CD**, and **TIOCM_CTS**.  The caller should use
          **TIOCGICOUNT** to see which bit has changed.

   **TIOCGICOUNT**
          Get counts of input serial line interrupts (DCD, RI, DSR,
          CTS).  The counts are written to the _serialicounterstruct_
          structure pointed to by _argp_.

          Note: both 1->0 and 0->1 transitions are counted, except
          for RI, where only 0->1 transitions are counted.

RETURN VALUE top

   On success, 0 is returned.  On error, -1 is returned, and _[errno](../man3/errno.3.html)_ is
   set to indicate the error.

EXAMPLES top

   Check the condition of DTR on the serial port.

   #include <asm/termbits.h>
   #include <fcntl.h>
   #include <stdio.h>
   #include <sys/ioctl.h>
   #include <unistd.h>

   int
   main(void)
   {
       int fd, serial;

       fd = open("/dev/ttyS0", O_RDONLY);
       ioctl(fd, TIOCMGET, &serial);
       if (serial & TIOCM_DTR)
           puts("TIOCM_DTR is set");
       else
           puts("TIOCM_DTR is not set");
       close(fd);
   }

SEE ALSO top

   [ioctl(2)](../man2/ioctl.2.html), [ioctl_tty(2)](../man2/ioctl%5Ftty.2.html)

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Linux man-pages 6.10 2024-11-03 TIOCMSET(2const)

Pages that refer to this page:ioctl_tty(2)