how to represent int64 in VB?


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Thread: how to represent int64 in VB?

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  1. #1
    - John of Arc - Guest

    how to represent int64 in VB?

    How does one represent large numbers like the int64 (e.g. file times) in VB?

    Thanks.



  2. #2
    Jonathan Wood Guest

    Re: how to represent int64 in VB?

    John <snip>,

    > How does one represent large numbers like the int64 (e.g. file times) in

    VB?

    The short answer is that VB doesn't support 64 bit integers.

    You could probably come up with a way to represent them using a Byte or Long
    array. For some tasks, using the Decimal data type of a variant might work.
    It depends on what you need to do with that int64.

    --
    Jonathan Wood
    SoftCircuits Programming
    http://www.softcircuits.com




  3. #3
    Anton Britten Guest

    Re: how to represent int64 in VB?

    If you are passing by reference pass the first long of a long array of two
    elements eg

    dim l(1 to 2) as long

    call someroutine(l(1))

    BUT don't forget the number will come back reversed

    so if you had a value 1 in the 64 bit number hex H00000000 00000001

    it will come back as

    l(1) = H00000001
    l(2) = H00000000 !!!!!!!

    BTW if you are J of A does it mean us English have got to burn you again - is
    that what you understand by a flame? :-)

    Anton

    - John of Arc - wrote:

    > How does one represent large numbers like the int64 (e.g. file times) in VB?
    >
    > Thanks.


    --

    Anton Britten

    EMail :- anton@brittena.demon.co.uk
    or AntonBritten@compuserve.com

    Web site :- www.brittena.demon.co.uk

    Anton Britten Computing Ltd
    You find sympathy in the dictionary
    - between sh*t and syphilis !



  4. #4
    Eduardo A. Morcillo Guest

    Re: how to represent int64 in VB?

    > The short answer is that VB doesn't support 64 bit integers.

    But it has a 64bits type: Currency.

    --
    Eduardo A. Morcillo
    http://www.domaindlx.com/e_morcillo



  5. #5
    - John of Arc - Guest

    Re: how to represent int64 in VB?

    Thanks for the technique.

    I'm trying to handle file times, to be more specific.


    Anton Britten <AntonBritten@compuserve.com> wrote in message
    news:38CB5F2C.5890DC91@compuserve.com...
    > If you are passing by reference pass the first long of a long array of two
    > elements eg
    >
    > dim l(1 to 2) as long
    >
    > call someroutine(l(1))
    >
    > BUT don't forget the number will come back reversed
    >
    > so if you had a value 1 in the 64 bit number hex H00000000 00000001
    >
    > it will come back as
    >
    > l(1) = H00000001
    > l(2) = H00000000 !!!!!!!
    >
    > BTW if you are J of A does it mean us English have got to burn you again -

    is
    > that what you understand by a flame? :-)
    >
    > Anton
    >
    > - John of Arc - wrote:
    >
    > > How does one represent large numbers like the int64 (e.g. file times) in

    VB?
    > >
    > > Thanks.

    >
    > --
    >
    > Anton Britten
    >
    > EMail :- anton@brittena.demon.co.uk
    > or AntonBritten@compuserve.com
    >
    > Web site :- www.brittena.demon.co.uk
    >
    > Anton Britten Computing Ltd
    > You find sympathy in the dictionary
    > - between sh*t and syphilis !
    >
    >




  6. #6
    Jonathan Wood Guest

    Re: how to represent int64 in VB?

    Currency is not an integer type.

    --
    Jonathan Wood
    SoftCircuits Programming
    http://www.softcircuits.com

    "Eduardo A. Morcillo" <edanmo@geocities.com> wrote in message
    news:38cb7ec1@news.devx.com...
    > > The short answer is that VB doesn't support 64 bit integers.

    >
    > But it has a 64bits type: Currency.
    >
    > --
    > Eduardo A. Morcillo
    > http://www.domaindlx.com/e_morcillo
    >
    >




  7. #7
    Karl E. Peterson Guest

    Re: how to represent int64 in VB?

    Hi Jonathan --

    >Currency is not an integer type.


    Close enough. It's a "scaled integer" and works fine for the original question.

    Later... Karl





  8. #8
    Karl E. Peterson Guest

    Re: how to represent int64 in VB?

    Hi John --

    >How does one represent large numbers like the int64 (e.g. file times) in VB?


    Here's what I use:

    Private Type FILETIME
    dwLowDateTime As Long
    dwHighDateTime As Long
    End Type

    You can see a complete example at http://www.mvps.org/vb -- FileInfo.zip on the
    Samples page.

    Later... Karl




  9. #9
    Jonathan Wood Guest

    Re: how to represent int64 in VB?

    Karl,

    > Close enough. It's a "scaled integer" and works fine for the original

    question.

    It may work for what he wanted but that wasn't really clear to me because he
    didn't indicate what he had to do with them.

    To me, the better approach is to use a combination of longs and, looking at
    your reply to him, looks like you agreed. :-)

    --
    Jonathan Wood
    SoftCircuits Programming
    http://www.softcircuits.com




  10. #10
    Eduardo A. Morcillo Guest

    Re: how to represent int64 in VB?

    You can replace FILETIME with Currency without any harm. Also you can use
    Currency with any function/callback that expects a 64bits interger. The only
    thing you have to do before passing it is divide it by 10000 and multiply it
    by 10000 after receiving it.

    --
    Eduardo A. Morcillo
    http://www.domaindlx.com/e_morcillo
    "Jonathan Wood" <jwood@softcircuits.com> wrote in message
    news:38cd35a8@news.devx.com...
    > Karl,
    >
    > > Close enough. It's a "scaled integer" and works fine for the original

    > question.
    >
    > It may work for what he wanted but that wasn't really clear to me because

    he
    > didn't indicate what he had to do with them.
    >
    > To me, the better approach is to use a combination of longs and, looking

    at
    > your reply to him, looks like you agreed. :-)
    >
    > --
    > Jonathan Wood
    > SoftCircuits Programming
    > http://www.softcircuits.com
    >
    >
    >






  11. #11
    Karl E. Peterson Guest

    Re: how to represent int64 in VB?

    Hi Jonathan --

    >> Close enough. It's a "scaled integer" and works fine for the original
    >> question.

    >
    >It may work for what he wanted but that wasn't really clear to me because he
    >didn't indicate what he had to do with them.


    I assumed he was using APIs that required a FILETIME structure.

    >To me, the better approach is to use a combination of longs and, looking at
    >your reply to him, looks like you agreed. :-)


    Yep, that's where I go with 'em. Jim Mack, and later (I believe) Bruce McKinney,
    published some cool routines that use Currency instead, so I guess opinions are mixed
    on this one.

    Later... Karl




  12. #12
    - John of Arc - Guest

    Re: how to represent int64 in VB?

    Aha!

    forgive my ignorance - what are the "low" and "high" parts? first 32 bits
    and second 32-bits?



    Karl E. Peterson <karl@mvps.org> wrote in message
    news:38cd2a7e$1@news.devx.com...
    > Hi John --
    >
    > >How does one represent large numbers like the int64 (e.g. file times) in

    VB?
    >
    > Here's what I use:
    >
    > Private Type FILETIME
    > dwLowDateTime As Long
    > dwHighDateTime As Long
    > End Type
    >
    > You can see a complete example at http://www.mvps.org/vb -- FileInfo.zip

    on the
    > Samples page.
    >
    > Later... Karl
    >
    >
    >




  13. #13
    Colin McGuigan Guest

    Re: how to represent int64 in VB?

    - John of Arc - wrote in message <38cdca8c$1@news.devx.com>...
    >Aha!
    >
    >forgive my ignorance - what are the "low" and "high" parts? first 32 bits
    >and second 32-bits?



    Yes; if you have a 64 bit number, you can split it into two 32-bit parts (or
    4 16-bit parts, etc, although it's less problematic to use the largest chunk
    possible).

    Mathematically, the low dword (4 bytes) would be your 64 bit number modulo
    2^32, whereas the high dword would be your 64 bit number, integer divided by
    2^32. I don't think the modulo operation in VB (mod) works with numbers
    above 2^31, tho.

    Programmatically, you're better off using CopyMemory.


    --
    Colin McGuigan




  14. #14
    Jonathan Wood Guest

    Re: how to represent int64 in VB?

    John <snip>,

    > How does one represent large numbers like the int64 (e.g. file times) in

    VB?

    The short answer is that VB doesn't support 64 bit integers.

    You could probably come up with a way to represent them using a Byte or Long
    array. For some tasks, using the Decimal data type of a variant might work.
    It depends on what you need to do with that int64.

    --
    Jonathan Wood
    SoftCircuits Programming
    http://www.softcircuits.com




  15. #15
    Anton Britten Guest

    Re: how to represent int64 in VB?

    If you are passing by reference pass the first long of a long array of two
    elements eg

    dim l(1 to 2) as long

    call someroutine(l(1))

    BUT don't forget the number will come back reversed

    so if you had a value 1 in the 64 bit number hex H00000000 00000001

    it will come back as

    l(1) = H00000001
    l(2) = H00000000 !!!!!!!

    BTW if you are J of A does it mean us English have got to burn you again - is
    that what you understand by a flame? :-)

    Anton

    - John of Arc - wrote:

    > How does one represent large numbers like the int64 (e.g. file times) in VB?
    >
    > Thanks.


    --

    Anton Britten

    EMail :- anton@brittena.demon.co.uk
    or AntonBritten@compuserve.com

    Web site :- www.brittena.demon.co.uk

    Anton Britten Computing Ltd
    You find sympathy in the dictionary
    - between sh*t and syphilis !



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