pipes in SCO UNIX 3.2V4.2,
It's long, long ago, so excuses for vagueness. I think the issue was
not pipe() perse, but the difference in functionality between 'pipe
filesystem' and streams pipes.
By using pipe() you create a FIFO pipe with certain limitations
(including 5120 write limit). When you open the streams device twice
and ioctl() two file descriptors together you have more flexibility.
Excuses for the possible confusion.