RMS v. CRTL: "ctx = stm" string Forces stream mode access. - VMS

This is a discussion on RMS v. CRTL: "ctx = stm" string Forces stream mode access. - VMS ; When I use the C RTL open() to open a file, I can specify "ctx=stm", which, according to the HELP, "Forces stream mode access". I'd be grateful if someone could tell me what, if anything, this does to the FAB, ...

+ Reply to Thread
Results 1 to 2 of 2

Thread: RMS v. CRTL: "ctx = stm" string Forces stream mode access.

  1. RMS v. CRTL: "ctx = stm" string Forces stream mode access.

    When I use the C RTL open() to open a file, I can specify "ctx=stm",
    which, according to the HELP, "Forces stream mode access". I'd be
    grateful if someone could tell me what, if anything, this does to the
    FAB, RAB, or any other RMS structure. (I'd like to be able to fiddle
    with this setting in an access callback function, but I don't know what
    it does where.)

    ------------------------------------------------------------------------

    Steven M. Schweda sms@antinode-org
    382 South Warwick Street (+1) 651-699-9818
    Saint Paul MN 55105-2547

  2. Re: RMS v. CRTL: "ctx = stm" string Forces stream mode access.

    On Dec 15, 2:41 am, s...@antinode.org (Steven M. Schweda) wrote:
    > When I use the C RTL open() to open a file, I can specify "ctx=stm",
    > which, according to the HELP, "Forces stream mode access". I'd be
    > grateful if someone could tell me what, if anything, this does to the
    > FAB, RAB, or any other RMS structure.


    It tells the CRTL to go ahead and use NON RMS byte access.
    The CRTL then uses RMS SYS$READ and SYS$WRITE calls to do BLOCKIO to
    the file and interprets the record structure itself.

    What it does to the RAB and FAB is best observed using ANALYZE/
    SYSTEM ... SET PROC ... SHOW PROC/RMS=(RAB,FAB,FSB)

    The FSB is the statistics block which of course will only be there if
    you have done a SET FILE/STATS before the open.

    hth,
    Hein.





    (I'd like to be able to fiddle
    > with this setting in an access callback function, but I don't know what
    > it does where.)
    >
    > ------------------------------------------------------------------------
    >
    > Steven M. Schweda sms@antinode-org
    > 382 South Warwick Street (+1) 651-699-9818
    > Saint Paul MN 55105-2547



+ Reply to Thread