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Inside Macintosh: Files /

Chapter 3 - Standard File Package / Standard File Package Reference

Application-Defined Routines / File Filter Functions

MyCustomFileFilter

A file filter function whose address is passed to CustomGetFile should have the following form:

FUNCTION MyCustomFileFilter (pb: CInfoPBPtr; myDataPtr: Ptr):
                               Boolean;

pb

A pointer to a catalog information parameter block.

myDataPtr

A pointer to the optional data whose address is passed to CustomGetFile.

DESCRIPTION

When CustomGetFile 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 pb parameter, a pointer to a catalog information parameter block. See the chapter "File Manager" in this book 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.

SEE ALSO

See "Writing a File Filter Function" on page 3-20 for a sample file filter function.