The CALLFH Compiler directive specifies the file handler used by your program to perform all COBOL I/O operations. By default, if no file handler is specified, the Micro Focus File Handler is used.
If you use the CALLFH Compiler directive to specify the Xfh2btr call conversion module, your program passes all I/O to the Xfh2btr call conversion module so that COBOL I/O operations are converted to Btrieve I/O operations.
You can include CALLFH at the top of your source program as an initial $SET statement as follows:
$set callfh"xfh2btr"