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Chapter 4 - Alias Manager / Alias Manager Reference

Alias Manager Routines / Creating and Updating Alias Records

UpdateAlias

You use the UpdateAlias function to update an alias record.

FUNCTION UpdateAlias (fromFile: FSSpecPtr; target: FSSpec;
                        alias: AliasHandle; 
                        VAR wasChanged: Boolean): OSErr;

fromFile

The starting point for a relative path, to be used later in a relative
search. If you do not need relative path information in the record, pass
a fromFile value of NIL. If you want UpdateAlias to record
relative path information, pass a pointer to a valid FSSpec record
in this parameter.

target

The target of the alias record. This parameter must be a valid
FSSpec record.

alias

A handle to the alias record to be updated.

wasChanged

A Boolean value indicating whether the newly constructed alias record is exactly the same as the old one. If the new record is the same as the old one, UpdateAlias sets the wasChanged parameter to FALSE. Otherwise, it sets it to TRUE. Check this parameter to determine whether you need to save an updated record.

DESCRIPTION

The UpdateAlias function updates the alias record pointed to by the alias parameter so that it describes the target specified by the target parameter. The UpdateAlias function rebuilds the entire alias record and fills it in as the NewAlias function would.

The UpdateAlias function always creates a complete alias record. When you use UpdateAlias to update a minimal alias record, you convert the minimal record to a complete record.

SPECIAL CONSIDERATIONS

The two files or directories, fromFile and target, must reside on the same volume.

ASSEMBLY-LANGUAGE INFORMATION

The trap macro and routine selector for UpdateAlias are

Trap macro	Selector
_AliasDispatch	$0006

RESULT CODES

noErr	0	No error
paramErr	-50	The value of the target or alias parameter, or both, is NIL, or the alias record is corrupt