ACC X.25 Protocol User's Guide

X.25 Application Programming
ZX25DBIT_ACK (3X) — ACC X.25
Chapter 4104
ZX25DBIT_ACK (3X) — ACC X.25
NAME zx25dbit_ack – Send acknowledgment for a data message with the D-bit
set
SYNOPSIS
#include <zcom/zcomsys.h>
#include <zcom/zcomx25.h>
int zx25dbit_ack (zxip, vzap)
zx25info_type *zxip;
zaddr_type *vzap;
DESCRIPTION Routine zx25dbit_ack requests that a D-bit acknowledgment (RR) be sent
in response to an inbound data message (or message fragment) which
had the D-bit set. That is, an X.25 level 3 RR should be transmitted to
acknowledge the last packet of the inbound message fragment that was
read (using zread). This function should only be called if the Virtual
Circuit has been configured for application end-to-end acknowledgments
by setting the APD bit in the VC’s option word definition. If the APD bit
in the option word has not been set, then the D-bit acknowledgment is
sent automatically by the X.25 firmware running on the ACC card and
the zx25dbit_ack function returns immediately without taking any
action.
This function must be called once for each message received (using
zread) that has the D-bit set. Failure to acknowledge each and every
inbound D-bit data message will result in the VC being reset (if the T25
timer is enabled) or hanging the VC (if T25 is disabled).
The libraries libzx25.a, libzcom_c.a, and libpthread.a must be linked into
the calling program by giving the “-lzx25 -lzcom_c -lpthread” options to
cc(1) or ld(1).