🚀 go-pugleaf

As quoted from <325@nsta.UUCP> by amos@nsta.UUCP (Amos Shapir):
+---------------
| One of the optional flags of the c_cflag field of termio is CLOCAL. (see
| <termio.h>)  It is  supposed  to  cause the  tty  driver  to ignore  the
| 'carrier detect' bit  in the RS232 interface, and open  the line anyway.
| This is needed for  ports that do not have the DC  wired; trying to open
| such a port without setting the CLOCAL bit first, will cause the open to
| hang forever waiting for a carrier signal.
| 
| However, the  only way to set  this flag is  by a ioctl call;  the ioctl
| call needs  a file-descriptor  argument; a  file-descriptor can  only be
| obtained by a successfull open call...
+---------------

#include <termio.h>
#include <fcntl.h>
#include <sys/ioctl.h>

...

	struct termio t;
	int fd;
	
	if ((fd = open("/dev/tty22", O_RDWR|O_NDELAY)) == -1) {
		perror("/dev/tty22");
		exit(1);
	}
	ioctl(fd, TCGETA, &t);
	t.c_cflag |= CLOCAL;
	ioctl(fd, TCSETAW, &t);

-- 
 Brandon S. Allbery, moderator of comp.sources.misc and comp.binaries.ibm.pc
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