Stream Pipes: how to use them on V.3/386

[Jerry Merlaine]

If you want to use UNIX V.3 Stream Pipes (like you're not supposed to),
here's how:  call the following routine instead of pipe(2) (look it up).
You will get a pair of cross-connected read/write Streams file descriptors.  

FDINSERT's are covered in streams(7) in the UNIX manual.
If you want your own stream pipe, get the Streams Programmer's Guide
and type in the loopback driver sources.  It's Fun And Easy!

#include <sys/types.h>
#include <sys/param.h>
#include <sys/stream.h>
#include <sys/stropts.h>

strpipe(pv)
int pv[2];
{
	struct strfdinsert fdi;

	pv[0] = open("/dev/spx", 2);
	pv[1] = open("/dev/spx", 2);
	if (pv[1] < 0) {
		close(pv[1]);
		if (pv[0] >= 0)
			close(pv[0]);
		return -1;
	}
	if (pv[0] < 0) 
		return -1;
	fdi.ctlbuf.buf = (char *) pv;
	fdi.ctlbuf.len = 4;
	fdi.databuf.buf = 0;
	fdi.databuf.len = -1;
	fdi.offset = 0;
	fdi.fildes = pv[1];
	fdi.flags = 0;
	if (ioctl(pv[0], I_FDINSERT, &fdi) < -1) {
		close(pv[0]);
		close(pv[1]);
		return -1;
	}
	return 0;
}