PKOPEN(3) (deprecated) PKOPEN(3)
NAME
pkopen, pkclose, pkread, pkwrite, pkfail - packet driver
simulator
SYNOPSIS
char *pkopen(fd)
pkclose(ptr)
char *ptr;
pkread(ptr, buffer, count)
char *ptr, *buffer;
pkwrite(ptr, buffer, count)
char *ptr, *buffer;
pkfail()
DESCRIPTION
These routines are a user-level implementation of the full-
duplex end-to-end communication protocol described in pk(4).
If fd is a file descriptor open for reading and writing,
pkopen carries out the initial synchronization and returns
an identifying pointer. The pointer is used as the first
parameter to pkread, pkwrite, and pkclose.
Pkread, pkwrite and pkclose behave analogously to read,
write and close(2). However, a write of zero bytes is mean-
ingful and will produce a corresponding read of zero bytes.
SEE ALSO
pk(4), pkon(2)
DIAGNOSTICS
Pkfail is called upon persistent breakdown of communication.
Pkfail must be supplied by the user.
Pkopen returns a null (0) pointer if packet protocol can not
be established.
Pkread returns -1 on end of file, 0 in correspondence with a
0-length write.
BUGS
This simulation of pk(4) leaves something to be desired in
needing special read and write routines, and in not being
inheritable across calls of exec(2). Its prime use is on
systems that lack pk.
These functions use alarm(2); simultaneous use of alarm for
other puposes may cause trouble.