Browse Prior Art Database

Automatic Detection of Missing Receive Buffer

IP.com Disclosure Number: IPCOM000101375D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Hoegh, BT: AUTHOR [+2]

Abstract

Disclosed is a method for the OS/2* Extended Edition Low Level Application Interface program(LLAPI) to detect when 3270 datastream structured field data has arrived for an application program and the application program has failed to define a buffer to receive it.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 61% of the total text.

Automatic Detection of Missing Receive Buffer

       Disclosed is a method for the OS/2* Extended Edition Low
Level Application Interface program(LLAPI) to detect when 3270
datastream structured field data has arrived for an application
program and the application program has failed to define a buffer to
receive it.

      In running OS/2 Extended Edition LLAPI applications such as the
Server Requester Programming Interface or File Transfer, data is
transferred to and from the host via 3270 datastream auxiliary device
structured fields. The normal course of action for an application to
receive host data is as follows:  The application program issues a
Define Buffer verb to the LLAPI to define a buffer for LLAPI to
receive each structured field transmission. LLAPI then issues a
similar request (Listen) to the SPI, passing along the buffer's
address and length.  This Listen verb is put on a queue which the
3270 emulator looks at whenever auxiliary device structured fields
arrive from the host.  When structured field data does arrive in any
given application, the emulator searches the Listen queue for a
buffer belonging to the that application.  If found, the SPI passes
it back to the LLAPI which passes it back to the application.

      Clearly, the LLAPI application must define the buffer with
LLAPI before any host is expected.  If, however, unexpected host data
comes in for the LLAPI application, the LLAPI application and the
host application can get out o...