Application Building Guide

Micro Focus COBOL

This section contains the following topics:

Using the Compiler
DB2 API and DB2 Embedded Applications
Embedded SQL Stored Procedures

Using the Compiler

If you develop applications that contain embedded SQL and DB2 API calls, and you are using the Micro Focus COBOL compiler, keep the following points in mind:

When you precompile your application using the command line processor command db2 prep, use the target mfcob option (the default).
In order to use the built-in precompiler front-end, run-time interpreter or Animator debugger, add the DB2 Generic API entry points to the Micro Focus run-time module rts32 by executing the mkrts command provided by Micro Focus, as follows:
1. Log in as root.
2. Execute mkrts with the arguments supplied in the following directory:
```
   /opt/IBMdb2/V7.1/lib/db2mkrts.args
```
You must include the DB2 COBOL COPY file directory in the Micro Focus COBOL environment variable COBCPY. The COBCPY environment variable specifies the location of COPY files. The DB2 COPY files for Micro Focus COBOL reside in sqllib/include/cobol_mf under the database instance directory.
To include the directory, enter:
```
   export COBCPY=$COBCPY:$HOME/sqllib/include/cobol_mf
```
Note: You might want to set COBCPY in the .profile file.

DB2 API and Embedded SQL Applications

The script file bldapp, in sqllib/samples/cobol_mf, contains the commands to build a DB2 application program.

The first parameter, $1, specifies the name of your source file. This is the only required parameter for programs that do not contain embedded SQL. Building embedded SQL programs requires a connection to the database so three optional parameters are also provided: the second parameter, $2, specifies the name of the database to which you want to connect; the third parameter, $3, specifies the user ID for the database, and $4 specifies the password.

For an embedded SQL program, bldapp passes the parameters to the precompile and bind file, embprep. If no database name is supplied, the default sample database is used. The user ID and password parameters are only needed if the instance where the program is built is different from the instance where the database is located.

#! /bin/ksh
# bldapp script file -- Solaris
# Builds a Micro Focus COBOL application program
# Usage: bldapp [ <db_name> [ <userid> <password> ]] 
 
# Set DB2PATH to where DB2 will be accessed.
# The default is the standard instance path.
DB2PATH=$HOME/sqllib
 
# If an embedded SQL program, precompile and bind it.
if [[ -f $1".sqb" ]]
then
  embprep $1 $2 $3 $4
fi
 
# Set COBCPY to include the DB2 COPY files directory.
export COBCPY=$DB2PATH/include/cobol_mf:$COBCPY
  
# Compile the checkerr.cbl error-checking utility.
cob -cx checkerr.cbl
  
# Compile the program.
cob -cx $1.cbl
  
# Link the program.
cob -x $1.o checkerr.o -L$DB2PATH/lib -ldb2 -ldb2gmf

Compile and Link Options for bldapp

Compile Options:

cob
The Micro Focus COBOL compiler.
-cx
Compile to object module.

Link Options:

cob
Use the compiler as a front end for the linker.
-x
Specify an executable program.
$1.o
Include the program object file.
checkerr.o
Include the utility object file for error-checking.
-L$DB2PATH/lib
Specify the location of the DB2 static and shared libraries at link-time. For example: $HOME/sqllib/lib.
-ldb2
Link with the DB2 library.
-ldb2gmf
Link with the DB2 exception-handler library for Micro Focus COBOL.

Refer to your compiler documentation for additional compiler options.

Compile and Link Options for bldapp
Compile Options: `cob` The Micro Focus COBOL compiler. `-cx` Compile to object module.
Link Options: `cob` Use the compiler as a front end for the linker. `-x` Specify an executable program. `$1.o` Include the program object file. `checkerr.o` Include the utility object file for error-checking. `-L$DB2PATH/lib` Specify the location of the DB2 static and shared libraries at link-time. For example: `$HOME/sqllib/lib`. `-ldb2` Link with the DB2 library. `-ldb2gmf` Link with the DB2 exception-handler library for Micro Focus COBOL. Refer to your compiler documentation for additional compiler options.

To build the non-embedded SQL sample program, client, from the source file client.cbl, enter:

   bldapp client

The result is an executable file client. You can run the executable file against the sample database by entering:

   client

Building and Running Embedded SQL Applications

There are three ways to build the embedded SQL application, updat, from the source file updat.sqb:

If connecting to the sample database on the same instance, enter:
```
   bldapp updat
```
If connecting to another database on the same instance, also enter the database name:
```
   bldapp updat database
```
If connecting to a database on another instance, also enter the user ID and password of the database instance:
```
   bldapp updat database userid password
```

The result is an executable file, updat.

There are three ways to run this embedded SQL application:

If accessing the sample database on the same instance, simply enter the executable name:
```
   updat
```
If accessing another database on the same instance, enter the executable name and the database name:
```
   updat database
```
If accessing a database on another instance, enter the executable name, database name, and user ID and password of the database instance:
```
   updat database userid password
```

Embedded SQL Stored Procedures

Notes:

Before building Micro Focus stored procedures on Solaris, run the following commands:
```
   db2stop
   db2set DB2LIBPATH=$LD_LIBRARY_PATH
   db2set DB2ENVLIST="COBDIR LD_LIBRARY_PATH"
   db2set
   db2start
```
Ensure that db2stop stops the database. The last db2set command is issued to check your settings: make sure DB2LIBPATH and DB2ENVLIST are set correctly.
Some of the more recent versions of the Micro Focus COBOL compiler used on Solaris cannot be used to create a statically-linked stored procedure. As such, the makefile and script file, bldsrv, have been adapted to allow for the creation of a dynamically-linked stored procedure.
In order for a remote client application to successfully call this dynamically-linked stored procedure, it is necessary for a Micro Focus COBOL routine, cobinit(), to be called on the server where the stored procedure resides just before the stored procedure is executed. A wrapper program which accomplishes this is created during the execution of the makefile, or the script file bldsrv. It is then linked with the stored procedure code to form the stored procedure shared library. Due to the use of this wrapper program, in order for a client application to call a stored procedure named x, it must call x_wrap instead of x.
The details of the wrapper program are explained later in this section.

The script file bldsrv, in sqllib/samples/cobol_mf, contains the commands to build a stored procedure. The script file compiles the stored procedure into a shared library that can be called by a client application.

The first parameter, $1, specifies the name of your source file. The second parameter, $2, specifies the name of the database to which you want to connect. Since the stored procedure must be build on the same instance where the database resides, there are no parameters for user ID and password.

Only the first parameter, source file name, is required. Database name is optional. If no database name is supplied, the program uses the default sample database.

The script file uses the source file name, $1, for the shared library name.

#! /bin/ksh 
# bldsrv script file -- Solaris
# Builds a Micro Focus COBOL stored procedure
# Usage: bldsrv <prog_name> [ <db_name> ] 
 
# Set DB2PATH to where DB2 will be accessed.
# The default is the standard instance path.
DB2PATH=$HOME/sqllib
 
# Precompile and bind the program.
embprep $1 $2
 
# Set COBCPY to include the DB2 COPY files directory.
export COBCPY=$DB2PATH/include/cobol_mf:$COBCPY
  
# Compile the program.
cob -cx $1.cbl
 
# Create the wrapper program for the stored procedure.
wrapsrv $1
 
# Link the program creating shared library $1 with main entry point ${1}_wrap
cob -x -o $1 ${1}_wrap.c $1.o -Q -G -L$DB2PATH/lib -ldb2 -ldb2gmf
 
# Copy the shared library to the sqllib/function subdirectory.
# The user must have write permission to this directory.
rm -f $DB2PATH/function/$1
cp $1 $DB2PATH/function

Compile and Link Options for bldsrv

Compile Options:

cob
The COBOL compiler.
-cx
Compile to object module.

Link Options:

cob
Use the compiler to link edit.
-x
Produce an executable program.
-o $1
Specify the executable program.
${1}_wrap.c
Specify the wrapper program.
$1.o
Specify the program object file.
-Q

-G

-L$DB2PATH/lib
Specify the location of the DB2 runtime shared libraries. For example: $HOME/sqllib/lib. If you do not specify the -L option, the compiler assumes the following path: /usr/lib:/lib.
-ldb2
Link to the DB2 library.
-ldb2gmf
Link to the DB2 exception-handler library for Micro Focus COBOL.

Refer to your compiler documentation for additional compiler options.

Compile and Link Options for bldsrv
Compile Options: `cob` The COBOL compiler. `-cx` Compile to object module.
Link Options: `cob` Use the compiler to link edit. `-x` Produce an executable program. `-o $1` Specify the executable program. `${1}_wrap.c` Specify the wrapper program. `$1.o` Specify the program object file. `-Q` `-G` `-L$DB2PATH/lib` Specify the location of the DB2 runtime shared libraries. For example: `$HOME/sqllib/lib`. If you do not specify the `-L` option, the compiler assumes the following path: `/usr/lib:/lib`. `-ldb2` Link to the DB2 library. `-ldb2gmf` Link to the DB2 exception-handler library for Micro Focus COBOL. Refer to your compiler documentation for additional compiler options.

The wrapper program, wrapsrv, causes the Micro Focus COBOL routine, cobinit(), to be called right before the stored procedure is executed. Its contents are shown below.

#! /bin/ksh # wrapsrv script file # Creates the wrapper program for Micro Focus COBOL stored procedures # Usage: wrapsrv <stored_proc> # Note: The client program calls "<stored_proc>_wrap" not "<stored_proc>" # Create the wrapper program for the stored procedure. cat << WRAPPER_CODE > ${1}_wrap.c #include <stdio.h> void cobinit(void); int $1(void *p0, void *p1, void *p2, void *p3); int main(void) { return 0; } int ${1}_wrap(void *p0, void *p1, void *p2, void *p3) { cobinit(); return $1(p0, p1, p2, p3); } WRAPPER_CODE

To build the sample program outsrv from the source file outsrv.sqb, if connecting to the sample database, enter:

   bldsrv outsrv

If connecting to another database, also enter the database name:

   bldsrv outsrv database

The script file copies the stored procedure to the server in the path sqllib/function.

If necessary, set the file mode for the stored procedure so the client application can access it.

Once you build the stored procedure outsrv, you can build the client application outcli that calls the stored procedure. You can build outcli using the script file, bldapp. Refer to "DB2 API and Embedded SQL Applications" for details.

To call the stored procedure, run the sample client application by entering:

   outcli database userid password

where

database: Is the name of the database to which you want to connect. The name could be sample, or its alias, or another name.
userid: Is a valid user ID.
password: Is a valid password.

The client application accesses the stored procedure library, outsrv, which executes the stored procedure function of the same name on the server database, and then returns the output to the client application.

Exiting the Stored Procedure

When you develop a stored procedure, exit the stored procedure using the following statement:

   move SQLZ-HOLD-PROC to return-code.

With this statement, the stored procedure returns correctly to the client application. This is especially important when the stored procedure is called by a local COBOL client application.

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