If you are opening an existing file, all file systems linked into the run time system are searched for the named file. If, however, you are creating a new file, you must tell the run time system which file system to use. You accomplish this with one of the following ACUCOBOL-GT runtime configuration file variables.
This designates the file system to be used for newly created files that are not individually assigned. For example,
means that all new files are Oracle files unless otherwise specified by another ACUCOBOL-GT runtime configuration file variable, which is:
where filename is the file name, without any extension, named in the ASSIGN TO clause of your SELECT statement. This configuration variable is used to assign an individual data file to a file system. Any file so assigned use the designated file system, and not the one specified by DEFAULT_HOST. For example,
means that myfile is under the Oracle file system.
You can use these ACUCOBOL-GT runtime configuration file variables in combination to assign your new files in a default with exceptions manner. For example, this set of entries:
DEFAULT_HOST ORACLE afile_HOST DB2 bfile_HOST DB2
means that all new files except afile and bfile are assigned to Oracle, and those two files are assigned to DB2.
You can change the values of these variables during program execution by including in your code:
SET ENVIRONMENT "filename_HOST" TO filesystem
SET ENVIRONMENT "DEFAULT_HOST" TO filesystem
This enables you to change file systems during the execution of your program. (This is not the typical way to specify a file system; normally it is designated in the ACUCOBOL-GT runtime configuration file and is not changed in the COBOL program.)