HP X.25/9000 Programmer's Guide

60 Chapter4

Sending and Receiving Data

Using Nonblocking I/O

the out-of-band queue. The process must not send a second INTERRUPT

packet until interrupt conﬁrmation has been received or a reset

indication has been received.

• ioctl() returns immediately. Most ioctl() values used by X.25 are

not directly related to transmiting and receiving packets. The

ioctl(X25_RESET_VC) and ioctl(X25_SEND_CALL_ACEPT) calls

cause the transmission of packets. Both of these ioctl() types cause

a packet to be sent. The ioctl(X25_SEND_CALL_ACEPT) never blocks

because all transmit buffers are empty when it is issued. The socket

is ready for transmission and reception.

When issued in nonblocking mode, the ioctl(X25_RESET_VC)

returns 0 and a RESET REQUEST packet is sent on the VC. When a

RESET CONFIRMATION packet is received, X.25 sends a SIGURG

signal and a

OOB_VC_RESET_CONF

event is added to the out-of-band

queue. No data of any sort may be sent by the process until the

conﬁrmation has been received.

36960-90061.bk Page 60 Friday, November 10, 2000 3:42 PM