[m-rev.] for review: bootstrap with MSVC as C compiler.

[Fergus Henderson]

On 07-Nov-2002, Peter Moulder <pmoulder at csse.monash.edu.au> wrote:
> > [code for sleep or Sleep]
> > +#else
> > +        /*
> > +        ** busy-wait for a few billion cycles, which should hopefully
> > +        ** take a second or more.
> > +        */
> > +        volatile int i;
> > +        for (i = 0; i < 100000000; i++)
> > +        {}
> >  #endif
> 
> I'm inclined to think that #error (or at least #warning, though my
> inclination is for #error) is the right thing here.  By all means
> leave some example code someone can use as a last resort.

The drawback of #error is that it prevents compilation.
This makes it more difficult for users to port Mercury to new systems.
Generally, when porting Mercury to a new system, worrying about the
vim support in the debugger is not your highest priority, but using
#error here would force it to be your highest priority -- even if
vim itself was not supported on the system that you are trying to port to.

> Rationale for drawing attention: The context of this code is waiting
> for a forked vim process to have started.  If fork exists but sleep
> doesn't (according to configure) then there's a good chance that it's
> just an error with the makefiles or configuration process, which the
> user would probably want to fix.

The code in question is not inside #ifdef MR_HAVE_FORK.
It uses system("... &") to invoke the server.

So I do not think it would be a good idea to use #error.

> [various suggestions on how to improve the code for this case]

These suggestions are good suggestions; complete, tested patches which
implement these suggestions would be welcome.

However, quality of the debugging support on systems that don't have sleep()
or _Sleep() is not a major priority, IMHO; developers are likely to
do their development on Linux or Windows and then port to other systems.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.
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