Inside Macintosh: QuickTime /

Chapter 2 - Movie Toolbox / Movie Toolbox Reference

Application-Defined Functions / File Filter Functions

MyFileFilter

A file filter function whose address is passed to SFGetFilePreview, StandardGetFilePreview, or CustomGetFilePreview should have the following form.

pascal Boolean MyFileFilter (ParmBlkPtr parmBlock);

paramBlock

A pointer to the parameter block associated with the files that are displayed to the user in this dialog box. For details, see Inside Macintosh: Files.

DESCRIPTION

When SFGetFilePreview, StandardGetFilePreview, or CustomGetFilePreview is displaying the contents of a volume or folder, it checks the file type of each file and filters out files whose types do not match your application's specifications. If your application also supplies a file filter function, the Standard File Package calls that function each time it identifies a file of an acceptable type.

When your file filter function is called, it is passed, in the paramBlock parameter, a pointer to a catalog information parameter block. See the chapter "File Manager" in Inside Macintosh: Files for a description of the fields of this parameter block.

Your function evaluates the catalog information parameter block and returns a Boolean value that determines whether the file is filtered (that is, a value of true suppresses display of the filename, and a value of false allows the display). If you do not supply a file filter function, the Standard File Package displays all files of the specified types.