New File Systems

Two types of tools are necessary to use your own file system with the HFS APIs. You must supply these tools:

• Exit programs that do the work for the HFS APIs. You must provide these exit programs. Exit programs enable application programs to use the specific HFS APIs to work with files and directories in your file system. The HFS Exit Program--Scenario that follows shows how an application creates a directory in your file system using an exit program.
• Programs that call the Register File System (QHFRGFS) and Deregister File System (QHFDRGFS) APIs. Registration makes your file system and its exit programs accessible to application programs using the HFS APIs. Deregistration lets you remove a file system from use.

Scenario: HFS Exit Program

Most exit programs correspond directly to APIs. For example, to allow applications to create directories in your file system, you must write an exit program that supplies the Create Directory function (CRTDR) for the Create Directory (QHFCRTDR) API. When an application calls an HFS API, the system routes the call to the appropriate exit program in the appropriate file system, according to the API's function and the file system name specified in the API's path-name parameter.

Note: The abbreviation CRTDR in the following illustration is the function name. See HFS Exit Programs for more information about function names.

Creating a Directory in Your File System