APPC Send and Receive TPs

These are simple APPC send and receive TPs that illustrate the use of asynchronous verb completion. This sample implements simple bulk data sending and receiving TPs (SENDTP and RECVTP).

Setup

To set up these TPs, create an appropriate APPC LU-LU-mode triplet. The default is SENDLU-RECVLU-#INTER, but this can be configured (see the following sections).

Input and Output

The APPC send and receive TPs each use a configuration file for input. To name the file, use .CFG as the extension, and use the same base file name as the TP executable file (SENDTP.CFG, for example). Save this configuration file in the same directory location as the executable file (the TP itself).

For SENDTP, the configuration file (called SENDTP.CFG if the executable file is SENDTP.EXE) can contain the following items, one per line, in any order. If a variable is not found in the file or the file is not present at all, the default is used.

Line Default value Value to supply
ResultFile = C:\SENDTP.OUT File name to print timings to
LocalLUAlias = SENDLU Local LU alias
RemoteLUAlias = RECVLU Remote LU alias
ModeName = #INTER Mode name
LocalTPName = SENDTP Name of local TP
RemoteTPName = RECVTP Name of remote TP
NumConversations = 1 Number of conversations
NumSends = 2 Number of SEND_DATA verbs per conversation
SendSize = 1024 Size in bytes of data sent each time
ConfirmEvery = 1 Number of SEND_DATA verbs between CONFIRM verbs
SendConversation = No Yes or No: Use the SEND_CONVERSATION verb rather than the sequence of ALLOCATE, SEND_DATA, DEALLOCATE

RECVTP uses a RECVTP.CFG file in a similar way, but only to read the LocalTPName field.

The output from SENDTP and RECVTP consists of details of the configuration and the time taken for each conversation, and is sent to the result file specified in SENDTP.CFG.

Operation

RECVTP should be started first; it issues RECEIVE_ALLOCATE with the specified TP name. SENDTP is then started; it first issues MC_SEND_CONVERSATION to tell RECVTP how many conversations will be carried out. It then carries out the specified number of conversations.

For SENDTP, each conversation consists of an MC_ALLOCATE verb, followed by a given number of MC_SEND_DATA verbs of a given size, and interspersed with MC_CONFIRM verbs at a given interval, followed by an MC_DEALLOCATE.

RECVTP issues MC_RECEIVE_AND_WAIT when RECEIVE_ALLOCATE completes, and then issues either MC_RECEIVE_AND_WAIT or MC_CONFIRMED according to the return from the previous MC_RECEIVE_AND_WAIT.

At any stage, if the TPs encounter an error, they terminate. Use APPC API tracing to diagnose problems with the configuration.

At the end of the specified number of conversations, SENDTP sends timing information to a file.

Both TPs are built from a single source code file, SENDRECV.C. SENDTP is compiled only if -DSENDTP is used on the command line.

The TPs run as Microsoft® Windows NT® or Microsoft® Windows® 95 applications with a minimized window, the title bar of which displays the status. When the WndProc of this window, TPWndProc, receives the WM_CREATE message for the window, this triggers the issuing of the first verb. When TPWndProc receives an ASYNC_COMPLETE message from Windows APPC, this triggers the issuing of the next verb, dependent on what the previous verb was. When the window is closed, WinAPPCCleanup is issued to terminate any active conversations.