From: karl@grebyn.com (Karl A. Nyberg)
Subject: Missing accept statement
Date: 16 Mar 90 03:25:27 GMT [thread overview]
Message-ID: <19466@grebyn.com> (raw)
In-Reply-To: 1990Mar15.203521.28171@planck.uucp
In article <1990Mar15.203521.28171@planck.uucp> westley@hercules.uucp () writes:
>Is it valid for a task body to be lacking an accept statement for a
>corresponding entry from the specification of that task? I can't find a
>specific rule in the RM, but this seems contrary to idea of the compiler
>catching this class of potential bugs.
ISO ARG AI-00373/00-co-RE (derived from a comment submitted on 85-08-04) reads:
It has come to my attention that at least one validated compiler
does not require that there be in a task body at least one occurence
of an accept statement (possibly within a selective wait) that
corresponds to each entry or entry family in the task specification.
After reviewing LRM 9, I conclude that there is no requirement that
every entry have a corresponding accept. The only statement that
seems to come close is in 9.5(1): ``The actions to be performed when
an entry is called are specified by corresponding accept
statements.'' This might lead one to expect that there will be
corresponding accept statements, but it hardly seems to state a
requirement.
Moreover, the entire semantics in 9.5 is stated in terms of what
happens when both an entry has been called and a corresponding
accept is reached. It follows that when there is no accept, any such
entry call will simply wait indefinitely. No semantic difficultly
results. (Obviously, even a textual occurence of an accept does not
assure that it will ever be reached or ever be open when reached.)
Is it intended that entries need not have a corresponding accept
statement, or is this an oversight? (Or is such a requirement
stated or implied in some less obvious place in the RM?)
RE status commentaries are: "A comment has been received that is not
relevant to an existing commentary, so a new commentray is created together
witha provisional classification of the point addressed by the comment. co
class commentaries are defined as "The point raised by the commentary can be
resolved by direct reference to the Standard; the point is not considered to
be of general interest."
That this commentary has languished in the ARG these past 4 plus years seems
to me sufficient indication that it is an accepted position.
-- Karl --
next prev parent reply other threads:[~1990-03-16 3:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
1990-03-15 20:35 Missing accept statement westley
1990-03-16 3:25 ` Karl A. Nyberg [this message]
1990-03-16 14:34 ` arny.b.engelson
1990-03-17 6:01 ` Barry Margolin
1990-03-19 18:29 ` Terry J. Westley
[not found] <203521@<1990Mar15>
1990-03-16 16:52 ` stt
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