APPX allows you to link an external file manager into the engine to replace or supplement its own file manager. The currently supported external file managers are Vision and C-ISAM on Unix or Unix-related systems only.
The files required to link an external file manager into APPX are now included with the installation materials. These files can be found in the “linkable” subdirectory created below the directory where you installed APPX. To link an external file manager into APPX, change directories to the linkable directory:
cd $APPXPATH/linkable
Now you must research the locations of your linkable archive files for either Vision or C-ISAM. These files must be obtained from ACUCOBOL or Informix, and may vary depending on the operating system you have. They may also vary depending on the version of Vision or C-ISAM you have. For Vision the filename is usually ‘runcbl.a’. For C-ISAM the filename is usually ‘libisam.a’. Specify the locations of these files when entering the command to create the new engine. In the examples below the parameters ‘cisam=...’ and ‘vision=...’ specify the locations of C-ISAM and Vision archive files respectively. You may enter zero, one or both of these parameters. Any parameter that is not entered will not be available in the new engine. Examples:
To create an engine with C-ISAM but no Vision:
make -f Makefile.relink appx cisam=location/libisam.a
To create an engine with Vision but no C-ISAM:
make -f Makefile.relink appx vision=location/runcbl.a
To create an engine with both interfaces:
make -f Makefile.relink appx vision=location/runcbl.a cisam=location/libisam.a
To create an engine with neither optional interface:
make -f Makefile.relink appx
When the make is done you should have a new APPX engine, which you will use in place of the one shipped with the standard release. To test the new engine, execute APPX without replacing the old engine with the following command:
./appx
To make a file use the Vision or C-ISAM interface you need to remove the existing file. If the file contains data you must export it first. Use Database Management for the appropriate database and application, and select the ‘Export’ option. Then scratch the existing file using the ‘Scratch’ option. Now you must indicate to APPX the appropriate file management system (FMS) to use. The specification is entered using the ‘File Specifications’ option. The column labeled ‘FMS’ must be changed to the correct value. The values are:
· ‘1’ = APPXIO (standard APPX file manager)
· ‘2’ = Vision
· ‘3’ = C-ISAM
· ‘4’ = Sybase
· ‘5’ = Oracle
· ‘6’ = ODBC
· ‘7’ = APPX/Net
You can select any FMS for any data file. Design and System Administration files must use FMS 1.
Once you have selected the correct FMS you will need to create the file by using the ‘Create’ option. If you receive an error you either selected the incorrect FMS value or mis-linked your engine. Contact your support center for assistance. If you exported old data you may now import it by using the ‘Import’ option in Database Management. If you are going to access this data with ACUCOBOL read the notes about APPX_PD_SIGNS below before importing your data.
If the engine functions correctly you should replace the standard APPX engine with your customized one. You should either backup the standard engine or rename it. The command to rename it is:
cd ..
mv appx appx.standard
Then copy in the new engine:
mv linkable/appx .
Change ownership and permissions:
chmod u+s appx
chown appx appx
You may now delete the linkable directory if you desire:
rm -r linkable
Your customized APPX is now installed.
APPX references the environment variable APPX_PD_SIGNS to determine what values should be used for the sign portion of a packed decimal number. By default APPX uses ‘C’ to indicate positive numbers and ‘D’ to indicate negative numbers. ACUCOBOL uses different values. If you are going to be exchanging data between APPX and ACUCOBOL programs you must set the value of APPX_PD_SIGNS to FD using the following line in your profile or APPX startup script:
export APPX_PD_SIGNS=FD
The first letter of APPX_PD_SIGNS is the value to use for positive numbers and the second letter is the value for negative numbers. NOTE: if you exported any data during the steps above and you are using ACUCOBOL (or some other language which uses different sign indicators), you must re-import your data with APPX_PD_SIGNS set correctly. The signs must be stored the same for all data accessed by APPX for a particular installation. If some of your data is stored in different FMS systems, you must export and re-import all of your data whenever changing the value of APPX_PD_SIGNS, or arithmetic comparisons and calculations may not work correctly.