Anyone know a good newsgroup for Linux

Discussion in 'C Programming' started by Dawn Minnis, Feb 10, 2005.

  1. Dawn Minnis

    Dawn Minnis Guest

    Hi

    I know you're not supposed to post OS specific questions on the newsgroup so
    does anyone know a good newsgroup - where there are actually people talking
    to eachother and not full of spam - where I can get advice on developing C
    for a command line driven interface in Linux?

    Any advice greatly appreciated.

    Kind regards
    Dawn
     
    Dawn Minnis, Feb 10, 2005
    #1
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  2. Dawn Minnis

    Lew Pitcher Guest

    -----BEGIN PGP SIGNED MESSAGE-----
    Hash: SHA1

    Try comp.os.linux.development.apps
    or comp.os.linux.development.system
    or comp.os.linux.misc
    or comp.os.linux.questions

    - --
    Lew Pitcher
    IT Specialist, Enterprise Data Systems,
    Enterprise Technology Solutions, TD Bank Financial Group

    (Opinions expressed are my own, not my employers')
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    iD8DBQFCC5P1agVFX4UWr64RAjsaAKCjrNdQInkml5oWHkxl3wMsC63XVgCg1HIY
    9U+1gVDifG5UvlyYcVD34LA=
    =Yl/n
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    Lew Pitcher, Feb 10, 2005
    #2
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  3. Try comp.os.linux.development.apps, that would seem to be the best fit.
    If you want a wider scope also have a look at comp.unix.programmer.

    Regards, Jens
     
    Jens.Toerring, Feb 10, 2005
    #3
  4. Dawn Minnis

    Dawn Minnis Guest

    Thanks for that

    I will try them out.

    Regards
    Dawn
     
    Dawn Minnis, Feb 10, 2005
    #4
  5. Since from your email address you're in the UK, you could look at
    < While a lot of the discussion there is about
    non-programming stuff (installing, using etc.) there are a number of
    knowledgable Linux programmers there and it is relatively low-traffic
    (compared to comp.lang.c for instance).

    (Non-UK people could also look at that newsgroup, but it is less likely
    to be on non-UK servers, I know that it is on the BTInternet one...)

    Chris C
     
    Chris Croughton, Feb 10, 2005
    #5
  6. Dawn Minnis

    Dawn Minnis Guest

    Hey

    Thanks for all that info. I have lots of groups now to look at.

    Thanks
     
    Dawn Minnis, Feb 10, 2005
    #6
  7. <posted & mailed>

    comp.os.linux.development.apps
    comp.os.linux.development.system
    comp.os.linux.misc
     
    James McIninch, Feb 11, 2005
    #7
  8. Dawn Minnis

    CBFalconer Guest

    If you were using Netscape I could give you specific instructions
    on how to search for a newsgroup that your ISP carries. I suggest
    you get rid of Outhouse Excess as soon as possible. It does some
    evil things (but not as evil as google groups !!). Mozilla or
    Thunderbird would be suitable, from mozilla.org (and free).

    As long as you stick to portable standard C you can ask away here.
    Very little, if anything, in most programs needs to be system
    specific. If you get in the habit of using standard C you will
    rarely have porting problems.
     
    CBFalconer, Feb 11, 2005
    #8
  9. Dawn Minnis

    CBFalconer Guest

    *** top-posting fixed ***

    Please also quickly get out of the Outhouse Excess encouraged habit
    of top-posting. Your answer belongs after, or possibly intermixed
    with, the material you are quoting, after suitable snipping of
    non-germane material.
     
    CBFalconer, Feb 11, 2005
    #9
  10. Dawn Minnis

    CBFalconer Guest

    Out of perversity I looked, and att does carry it (and 600 odd
    other in the uk group) here in left-pondia.
     
    CBFalconer, Feb 11, 2005
    #10
  11. Oh yes, many non-UK servers do carry uk.* newsgroups (some of them, like
    the Berlin university public server news.individual.net, carry them on
    auto-create), but they are less likely to do so than UK servers in
    general, I've had (as UK Usenet Control) a number of queries "Where can
    I get uk.<x> newsgroup, my ISP doesn't have it?" from people using
    non-UK servers. I usually direct them to the free (for individuals)
    server above, or for companies to gradwell.net.

    Chris C
     
    Chris Croughton, Feb 11, 2005
    #11
  12. Dawn Minnis

    Dawn Minnis Guest

    Ok, well any chance someone could give me a quick explanation of what this
    single line means?

    Based on I, K and lda being integers
    #define A(I,J) a[(I)-1 + ((J)-1)* ( *lda)]

    If someone could just explain that one line to me i would be very grateful

    The rest of the top of the program looks like this:







    /* Subroutine */ int dgemm_(char *transa, char *transb, integer *m, integer
    *
    n, integer *k, doublereal *alpha, doublereal *a, integer *lda,
    doublereal *b, integer *ldb, doublereal *beta, doublereal *c, integer
    *ldc)
    {


    /* System generated locals */
    integer a_dim1, a_offset, b_dim1, b_offset, c_dim1, c_offset, i__1,
    i__2,
    i__3;

    /* Local variables */
    static integer info;
    static logical nota, notb;
    static doublereal temp;
    static integer i, j, l, ncola;
    extern logical lsame_(char *, char *);
    static integer nrowa, nrowb;
    extern /* Subroutine */ int xerbla_(char *, integer *);


    /*
    Parameter adjustments
    Function Body */

    #define A(I,J) a[(I)-1 + ((J)-1)* ( *lda)]
    #define B(I,J) b[(I)-1 + ((J)-1)* ( *ldb)]
    #define C(I,J) c[(I)-1 + ((J)-1)* ( *ldc)]
     
    Dawn Minnis, Feb 11, 2005
    #12
  13. It is doing treating an one dimentional array as a 1 based two
    dimensional array. In C arrays are 0 based (i.e a[0] is the first
    element). They want this array to be one based.

    lda is not an integer, it is a pointer to an integer, which presumably
    has the number of elements in the row.

    e.g. if there are 10 elements in a row

    A(1,1) -> a[0]; /* first element in first row */
    A(2,1) -> a[1]; / second element in first row */
    A(1,2) -> a[10]; /* first element in second row */

    -David
     
    David Resnick, Feb 11, 2005
    #13
  14. looks to me like an extract from Numerical Recipes in C, trying to use a
    C-style one-dimensional array "a" as if it were a fortran-style 1-based
    2-dimensional array "A". I and J are the row/column indices, and Ida is the
    row width. They subtract one because they can't concieve of arrays starting
    from zero.

    Throw away that book, and buy the new edition, which was rewritten by
    people who actually programmed in C.
     
    Mark McIntyre, Feb 11, 2005
    #14
  15. Dawn Minnis

    CBFalconer Guest

    If lda is an integer it will generate syntax errors. lda needs to
    be a pointer to an integer. It looks like it is trying to map a 1
    based indexing scheme into Cs zero based indexing. It will blow up
    badly for I or J values of zero.
     
    CBFalconer, Feb 11, 2005
    #15
  16. Dawn Minnis

    Dawn Minnis Guest

    Thanks guys.

    Its a line from the resulting C file after putting dgemm.f through the f2c
    converter. The result it genuine C code but it looks horrid. But thanks
    for explaining that to me. I wasnt aware that you could do that in C.

    Regards
    Dawn
     
    Dawn Minnis, Feb 11, 2005
    #16
  17. You can, but its dangerous, as it could invoke undefined behaviour for some
    values of I and J. Better to understand the algo and write your own C.
     
    Mark McIntyre, Feb 11, 2005
    #17
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