Exit Program for Set Stream File Size (QHFSETSZ) API

Before applications can use the Set Stream File Size (QHFSETSZ) API with your file system, you must:

1. Write an exit program that performs the set size operation on behalf of the API. For a detailed description of the API and its calling parameters, see Set Stream File Size (QHFSETSZ) API.
   
   
2. Give the exit program's name when you register the file system with the Register File System (QHFRGFS) API.

After that, when an application calls the QHFSETSZ API, the API calls your exit program and passes it the parameters specified by the application. Your exit program performs the work and returns any data to the API. The API passes the data back to the calling application.

Authorities and Locks

None.

Required Parameter Group

The API passes this information to your exit program:

Operation (SETSZ)

INPUT; CHAR(5)

The abbreviation for the operation being performed (SETSZ).

File system job handle

INPUT; CHAR(16)

The work area or job identifier for use by the file system.

The following parameters are the same as the parameters for the API.

Open file handle

INPUT; CHAR(16)

File size

INPUT; BINARY(4) UNSIGNED

API Functions

The QHFSETSZ API performs the standard functions described in Standard HFS API Functions.

Exit Program Requirements

You must create an exit program that performs the standard functions described in Standard HFS Exit Program Requirements and these additional functions:

• Checks for byte locks that conflict with changing the size of the file, and returns an exception if any are found. The application cannot set the file size into or beyond a locked range.
  
  
• Verifies that the file size parameter value is valid for that file system.
  
  
• Increases or decreases the file size.

Error Messages for Exit Program Use

This section lists the messages that the exit program can return to the API.