Proposed resolution (September, 2009): Change 6.10.1 [intro.execution] paragraph 3 as follows: Change 6.10.1 [intro.execution] paragraph 5 as follows: Delete 6.10.1 [intro.execution] paragraph 6, including the
footnote: Change 6.10.1 [intro.execution] paragraph 9 as follows: The least requirements on a conforming implementation are: Access to volatile objects are evaluated strictly according
to the rules of the abstract machine. At program termination, all data written into files shall be
identical to one of the possible results that execution of the program
according to the abstract semantics would have produced. The input and output dynamics of interactive devices shall take
place in such a fashion that
These collectively are referred to as the observable behavior
of the program. [Note: more stringent correspondences
between abstract and actual semantics may be defined by each
implementation. —end note] (Note; this resolution also resolves issue 612.)
...An instance of the abstract machine can thus have more than one
possible execution
sequence for a given program and a given input.
A conforming implementation executing a well-formed program shall
produce the same observable behavior as one of the possible
execution sequences executions of the
corresponding instance of the abstract machine with the same program
and the same input. However, if any such execution sequence
contains an undefined operation, this International Standard places no
requirement on the implementation executing that program with that
input (not even with regard to operations preceding the first
undefined operation).
The observable behavior of the abstract machine is its sequence
of reads and writes to volatile data and calls to library I/O
functions. [Footnote: An implementation can offer additional
library I/O functions as an extension. Implementations that do so
should treat calls to those functions as “observable
behavior” as well. —end footnote]
prompting messages actually appear
prior to a program waiting prompting output is actually
delivered before a program waits for input. What constitutes an
interactive device is implementation-defined.