Re: C bug of the day

[LLeweLLyn <llewelly.at@xmission.dot.com>]

Wesley Groleau <wesgroleau@despammed.com> writes:

 >  >
 >  > One point where I'm pretty sure Ada 83 didn't have the right default
 >  > (although they may have fixed it in Ada 95): garbage collection.  While
 >  > there are places where it is necessary to turn garbage collection off
 >  > (which seriously limits the use of a language in which you cannot have
 >  > untraced pointers, which the garbage collector cannot see), the safe
 >  > option is obviously to have it on by default, no?
 >
 > In Ada, GC is automatic for stack variables,
[snip]

In C++ GC is automatic for stack variables as well - and via
     constructors and destructors, one can leverage that to make it
     automatic for many kinds of dynamic variables. This isn't a
     complete solution however - one sometimes ends up with a few dynamic
     objects for which no readlily availible smart pointer is suitable.

 > but it
 > was intentionally left up to the vendor for access types
 > (which in Ada only exist when the programmer explicitly
 > declares them) because in some applications, it could
 > cause timing problems.  However, Ada 95 did add the ability
 > for the programmer to define whether GC occurs for any particular
 > data type, as well as to define how it occurs.

What do you mean by 'define how it occurs'? In C++ one 'defines how it
     occurs' by overloading new and delete, writing a smart pointer, or
     downloading an appropriate smart pointer or garbage
     collector. This is hardly the most convient way (for a programmer
     using C++), but it has oodles of flexibility.

 >
 >  > 2) you can generally "work around" the safety checks if necessary
 >  > (hopefully on a case by case basis, using source code constructs;
 >  > e.g. by writing array.unsafe_at( index ) rather than array[ index ]).
 >
 > Actually, it's something like
 > pragma Suppress ( <type-of-check>, <entity> );
[snip]

I think in another post I provided a link to what the rm95 has to say
     about this.

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