[comp.sys.mac.system] Limitations of aliases in System 7.0

ccc_ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University) (07/08/90)

Aliases in System 7.0 are implemented as files with special information
in them. When you select an alias from the Finder or Standard File,
they will automatically resolve the reference and return the "real"
file to the application.

However, if the application looks for a file itself (e g a preferences
file), there is no automatic resolution of aliases; the application
has to check for this situation and call the Alias Manager itself.

I guess this is only a minor problem; I hit it when I tried to create
an alias for the Scrapbook File from my System 6.0.5 folder (which
is going to stay on my hard disk, thank you, until System 7.0 is a
*lot* more stable). The Scrapbook complained that the file didn't
have the right format. In the end I fixed this by copying the Scrapbook
File itself.

Could alias resolution have been embedded more deeply into the File
Manager? That is, PBOpen, OpenResFile and OpenRFPerm could automatically
resolve aliases if presented with them; you'd need some mechanism for
explicitly overriding this (otherwise you'd have difficulty creating
and manipulating the aliases themselves!), but existing applications
would then support aliases on all file references automatically.

Lawrence D'Oliveiro                       fone: +64-71-562-889
Computer Services Dept                     fax: +64-71-384-066
University of Waikato            electric mail: ldo@waikato.ac.nz
Hamilton, New Zealand    37^ 47' 29" S, 175^ 19' 16" E, GMT+12:00
It reflects on the state of the computing industry when the revolutionary
advance is seen to be, not getting an idea to work, but getting it
to work under Unix.

alexr@ucscb.ucsc.edu (Alexander M. Rosenberg) (07/10/90)

In article <963.269743d4@waikato.ac.nz> ccc_ldo@waikato.ac.nz (Lawrence 
D'Oliveiro, Waikato University) writes:
> Aliases in System 7.0 are implemented as files with special information
> in them. When you select an alias from the Finder or Standard File,
> they will automatically resolve the reference and return the "real"
> file to the application.

Actually, aliases are just a data structure. Their presence as a file is 
the way that the Finder and Standard File use them. For example, there is 
an alias in the System file that points to the currently chosen printer 
driver.

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