This document describes how to build a server application using the IBM i ILE language CL. The sample server will be named SENDMESS. Using the IBM i command SNGPGMMSG (send program message), it sends a message to a given IBM i user and returns a confirmation to the RPC client. This document covers the following topics:

• Creating the Client/Server Interface

• Creating a Sample Server in CL

• Verifying the Server

---

Creating the Client/Server Interface

Using the Designer on your PC, create a Software AG IDL file similar to the following:

Library 'EXAMPLE' Is
 Program 'SENDMESS' Is
  Define Data Parameter
   1 UserID           (A10)  In
   1 Message_Text     (A70)  In
   1 Confirmation     (A40)  Out
  End-Define

Creating a Sample Server in CL

The server is implemented as an ILE CL program of type *PGM.

For our IDL example SENDMESS, the implemented server looks similar to the example below:

        PGM        PARM(&USER &MESSTEXT &CONFIRM)
 /*--------------------------------------------------------------------*/
        DCL        VAR(&USER) TYPE(*CHAR) LEN(10)     /* the user ID   */
        DCL        VAR(&MESSTEXT) TYPE(*CHAR) LEN(70) /* the text      */
        DCL        VAR(&CONFIRM) TYPE(*CHAR) LEN(40)  /* returned text */
 /*--------------------------------------------------------------------*/
        CHGVAR     VAR(&CONFIRM) VALUE(' ')           /* clean it */
        SNDPGMMSG  MSG(&MESSTEXT) TOUSR(&USER) MSGTYPE(*COMP)

        MONMSG     MSGID(CPF0000) EXEC(GOTO CMDLBL(BAD))
        CHGVAR     VAR(&CONFIRM) +
           VALUE('Message sent to user' *BCAT &USER)
        GOTO       CMDLBL(DONE)                       /* sending was ok */
 /*---------------------------------------------------------------------*/
 BAD:   CHGVAR     VAR(&CONFIRM) +
           VALUE('Message sending failed')
 DONE:  ENDPGM

Because servers are running in a multithreaded environment, your application programs must be thread-safe. This implies that all commands and subprograms accessed in your servers must allow multithreads.

Compiling and Linking the Server

Compile the server source using the IBM i command CRTBNDCL (create bound CL program).

The following example procedure demonstrates how to compile and bind an ILE CL program:

          PGM        /* Compile and Bind a CL Server program         */
 /*------------------------------------------------------------------*/
          DCL        VAR(&MODNAME) TYPE(*CHAR) LEN(10) VALUE(SENDMESS)
          DCL        VAR(&LIBL) TYPE(*CHAR) LEN(10) VALUE(EXAMPLE)
          DCL        VAR(&SRCF) TYPE(*CHAR) LEN(10) VALUE(QCLSRC)
          DCL        VAR(&OPTL) TYPE(*CHAR) LEN(10) VALUE(*NONE)
          DCL        VAR(&DBGV) TYPE(*CHAR) LEN(10) VALUE(*ALL)
 /*------------------------------------------------------------------*/
          MONMSG     MSGID(CPF6801) EXEC(GOTO CMDLBL(DONE))
                     /* If PF12 is pressed */

          CRTBNDCL   ??PGM(&LIBL/&MODNAME) ??SRCFILE(&LIBL/&SRCF) +
                     ??SRCMBR(&MODNAME) DFTACTGRP(*NO) +
                       ACTGRP(*CALLER) OUTPUT(*PRINT) +
                       OPTIMIZE(&OPTL) DBGVIEW(&DBGV)

          MONMSG     MSGID(LNC9001) EXEC(GOTO CMDLBL(ERRXT))
          GOTO       CMDLBL(DONE)
 /*------------------------------------------------------------------*/
  ERRXT:  SNDPGMMSG  MSG('MSG: Program Linkage Failed')
  DONE:   RETURN
          ENDPGM

Name the resulting server program like the program name in the IDL file and put it in a library whose name corresponds to the library name in the IDL file.

Example:

If a client performs a request that is based on the IDL program SENDMESS in the IDL library EXAMPLE, the ILE server program SENDMESS in the IBM i library EXAMPLE is executed. If no corresponding program can be found, the access will fail.

Verifying the Server

To verify the server program SENDMESS, use the EntireX IDL Tester when the RPC Server for AS/400 and EntireX Broker are used.

To verify the server

1. Confirm that an EntireX Broker and an RPC Server for AS/400 are available in your network.

2. Make sure the IBM i host server is started on your IBM i machine.

3. Create a Software AG IDL File using the IDL Editor as described under Creating the Client/Server Interface.

4. Start the IDL Tester.