v7 man page for pkopen

PKOPEN(3)						     Library Functions Manual							 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 meaningful 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.

								    deprecated								 PKOPEN(3)