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From: GG.SPY%ISUMVS%CUNYVM.CUNY.EDU%KL.SRI.COM%lbl%sfsu1.hepnet@LBL.GOV
Newsgroups: comp.os.vms
Subject: Re: LIB$INIT_TIMER
Message-ID: <880528235248.23e037b4@LBL.Gov>
Date: 29 May 88 06:52:48 GMT
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Organization: The Internet
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Date:      Thu, 26 May 88 08:34:35 CDT
To:        <INFO-VAX@KL.SRI.COM>
From:      "John Hascall" <GG.SPY%ISUMVS.BITNET@CUNYVM.CUNY.EDU>
Subject:   Re: LIB$INIT_TIMER
 
> Date:         Sat, 21 May 88 16:15:53 PST
> Sender:       INFO-VAX Discussion <INFO-VAX@UBVM>
> From:         Peter Scott <PJS@grouch.JPL.NASA.GOV>
> Subject:      LIB$INIT_TIMER
> To:           John Hascall <GA.JPH@ISUMVS>
>
> The documentation for LIB$INIT_TIMER states that it takes different actions
> base on whether the argument handle-adr is absent, zero, or non-zero.
>
> How do you get the "absent" effect when calling from C?  I have invariably
> found that I have to specify a 0 explicitly as a parameter when calling
> system routines where if I were using FORTRAN I would leave the argument
> blank.
>
> Peter Scott (pjs%grouch@jpl-mil.jpl.nasa.gov)
 
  When a VMS routine's parameter is passed by reference (pass the address of
the parameter) or by descriptor (pass the address of a block describing the
parameter) then to "omit the parameter" means to pass the value 0 (zero).
[FORTRAN does this for you when you leave a parameter blank].
 
John Hascall
ISU Computation Center
Ames, Iowa