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From: jb@rti.rti.org (Jeff Bartlett)
Newsgroups: comp.lang.ada,comp.compilers
Subject: Re: ADA Compiling Query
Summary: call by ref vs copyin-copyout
Keywords: Ada
Message-ID: <1991Feb13.211643.25777@rti.rti.org>
Date: 13 Feb 91 21:16:43 GMT
References: <5572@baird.cs.strath.ac.uk>
Sender: compilers-sender@iecc.cambridge.ma.us
Reply-To: jb@rti.rti.org (Jeff Bartlett)
Followup-To: comp.lang.ada
Organization: Research Triangle Institute, RTP, NC
List-Id: <comp.lang.ada>

In article <5572@baird.cs.strath.ac.uk>, gor@cs.strath.ac.uk (Gordon Russell) writes:
> [ does Ada pass arguments by reference or copy in/copy out?]

See ANSI/MIL-STD-1815A section 6.2 paragraph 7:

    .... The language does not define which of these two mechanisms is to
    be adopted for parameter passing, nor whether different calls to the
    same subprogram are to use the same mechanism.   The execution of a
    program is erroneous if its effect depends on which mechanism is
    selected by the implementation.

And section 1.6 paragraph 6:

    (c) Erroneous execution.

    The language rules specify certain rules to be obeyed by Ada programs,
    although there is no requirement on Ada compilers to provide either a
    compilation-time or run-time detection of the violation of such
    rules. .... The effect of erroneous execution is unpredictable.

Jeff Bartlett
Center for Digital Systems Research
Research Triangle Institute
jb@rti.rti.org       mcnc!rti!jb	(919)-541-6945
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