EA questions - OS2

This is a discussion on EA questions - OS2 ; Hi, I am working with EAs these days and have framed a couple of questions. As part of a system I am writing, I want to allow the user to simply retrieve all EAs either as a string, byte array ...

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  1. EA questions

    Hi,

    I am working with EAs these days and have framed a couple of questions.
    As part of a system I am writing, I want to allow the user to simply
    retrieve all EAs either as a string, byte array or a linked list of
    these. Part of this might be allowing for backing these up or sending
    them with a file over a network.

    First off, what are the formats for the binary EAs in .ASSOCTABLE,
    ..ICONPOS and such? Are these just some standard data type (e.g.
    ICONINFO)?

    Are the REXX EAs documented anyplace? For that matter, is there a REXX
    developers toolkit for writing things like REXX extensions?

    Any old (except for reserved types) type can be used for an EA, right?
    (just a reality check)

    If the EA is of type EAT_MVMT or EAT_MVST these can have any custom EA
    saved to them, right? I ask since one can list several of these but
    unless the entries are length preceeded there is no way of telling what
    is there.

    What is the strategy people use for dealing with unknown EAs? I know
    there are some nifty tools for looking at EAs, but in practice most of
    the time these will be either one of the standard EAs or something
    exotic.

    Here is a possible case. Let us say that I have what looks like a
    multivalued EA with n entries. If all of these are
    application-specific, should I just hand back the whole thing as a byte
    array? What I don't want to do is, say, back these up somehow and then
    find they are messed up on the restore.

    Any good places to look at examples of how people have worked with EAs?


    [Editorial note: That is one $%## API! Nasty, nasty, nasty...]
    Cheers,

    Jeff


  2. Re: EA questions

    On Mon, 17 Jan 2005 17:44:37 UTC, spam@jqhome.net wrote:

    > Hi,
    >
    > I am working with EAs these days and have framed a couple of questions.
    > As part of a system I am writing, I want to allow the user to simply
    > retrieve all EAs either as a string, byte array or a linked list of
    > these. Part of this might be allowing for backing these up or sending
    > them with a file over a network.


    You should read carefully what the documentation about EAs have to
    say.
    For that the best way is to install the toolkt42 coming with your
    eComStation.


    > If the EA is of type EAT_MVMT or EAT_MVST these can have any custom EA
    > saved to them, right?


    Yes. But you would onyl create an EA of that type when your specific
    logic would need that.

    True it is not too easy to design the EAs of an file right - but what
    is easy in programming anyway?
    You will start finding the right EA type using one of the standard
    defined types so long the data you have to store matches them.

    I ask since one can list several of these but
    > unless the entries are length preceeded there is no way of telling what
    > is there.
    >
    > What is the strategy people use for dealing with unknown EAs? I know
    > there are some nifty tools for looking at EAs, but in practice most of
    > the time these will be either one of the standard EAs or something
    > exotic.


    That is the trick to have different EAs with different types. Type and
    lengh fields lets you go over EAs you knows nothing about. Defining
    you own type can help you to hide some information frm other apps.

    > Here is a possible case. Let us say that I have what looks like a
    > multivalued EA with n entries. If all of these are
    > application-specific, should I just hand back the whole thing as a byte
    > array? What I don't want to do is, say, back these up somehow and then
    > find they are messed up on the restore.


    Follow the definition of the the type! When you does NOT so you will
    alive some strange behavior of the system and/or the apps using that
    type.

    > Any good places to look at examples of how people have worked with EAs?


    os2tlkt42.zip. Unzip and install the whole toolkit to find the
    examples and extended documentation about EAs.


    --
    Tschau/Bye
    Herbert

    Visit http://www.ecomstation.de the home of german eComStation
    eComStation 1.2 Deutsch ist da!

  3. Re: EA questions

    Jeff wrote:

    > Any good places to look at examples of how people have worked with EAs?


    + my filetype recognition/archivlister program Typ2
    + cmd.exe /c type -ea:FILENAME

    But there exist some broken resource compiler versions, that
    write corrupted EA. The REXX EA also do not follow the standard
    format, but they are an easiely handled special case.

    --
    Veit Kannegieser

  4. Re: EA questions

    Here is some weirdness I've noticed.

    I am able to read EAs with my program. The odd thing is that if I take
    a directory and fill in some keywords in the field then try to read, I
    get the error from DosQueryPathInfo that the EA list is inconsistent
    and there is an EA with no name that is the max of 64k. What gives? I
    am going thru the usual dialog in PM and just reading them.
    Suggestions??

    Jeff


  5. Re: EA questions

    On 17.01.05 18:44, spam@jqhome.net wrote:

    > Any good places to look at examples of how people have worked with
    > EAs?


    Cristian Langanke's WPS Toolkit: http://wpstk.netlabs.org

    --
    Andreas Schnellbacher

  6. Re: EA questions

    Solution: the chain of EAPO2 structures was not set up correctly.
    Grrr. such a friendly API...

    -- j


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