Introduction to Networking for NonStop S-Series Servers

Application Programming With Communications
Products
Introduction to Networking for HP NonStop S-Series Servers—520670-005
3-17
Typical Order of Calls
Request Management
General Information
Typical Order of Calls
The sequence of calls varies with the application, the process providing the application
interface, and the protocol. Here is a typical sequence for the X25AM IOP:
1. FILE_OPEN_ to gain access to the line and the subdevice (in this case a virtual
circuit), to determine whether access is exclusive or shared, and optionally to
specify nowait access and the number of concurrent requests allowed.
2. SETMODE to set the destination address.
3. CONTROL to initiate an outgoing call request.
4. WRITE[X] to send data, and READ[X] to receive data.
5. CONTROL to issue a call clear request.
FILE_CLOSE_ when the application no longer needs access to the line.
AWAITIO[X] Completes a request in cases of nowait access. Use AWAITIOX
with the extended 32-bit (or X) versions of the I/O procedures
such as READX, WRITEREADX, and so on. Use AWAITO with
the 16-bit versions such as READ, WRITEREAD, and so on.
CANCEL Cancels the oldest request pending for the process, line, or
subdevice.
CANCELREQ Cancels a specific request.
FILE_GETINFOBYNAME_ Reports the device type and physical record
length of the line, as defined to the operating
system.
FILE_GETINFOLISTBYNAME_ Reports the last file-system error and other
information related to the line or subdevice.