plucky (2) TIOCMGET.2const.gz

NAME

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

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #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

       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
              serial_icounter_struct 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

       On success, 0 is returned.  On error, -1 is returned, and errno is set to indicate the error.

EXAMPLES

       Check the condition of DTR on the serial port.

       #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

       ioctl(2), ioctl_tty(2)