Re: what is defined, was for or against equality

David Brown <david.brown@hesbynett.no> schrieb:


> There is no need to memorize undefined behaviours for a language -
> indeed, such a thing is impossible since everything not defined by a
> language standard is, by definition, undefined behaviour. (C and C++
> are not special here - the unusual thing is just that their standards
> say this explicitly.)


This is a rather C-centric view of things. The Fortran standard
uses a different model.


There are constraints, which are numbered. Any violation of such
a constraint needs to be reported by the compiler ("processor",
in Fortran parlance). If it fails to do so, this is a bug in
the compiler.


There are also phrases which have "shall" or "shall not". If this
is violated, this is an error in the program. Catching such a
violation is a good thing from quality of implementation standpoint,
but is not required. Many run-time errors such as array overruns
fall into this category.


[...]


> The real challenge from big languages and big standard libraries is not
> /writing/ code, it is /reading/ it. It doesn't really matter if a C
> programmer, when writing some code, does not know what the syntax "void
> foo(int a[static 10]);" means. (Most C programmers don't know it, and
> never miss it.) But it can be a problem if they have to read and
> understand code that uses something they don't know.


Agreed.

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