[m-dev.] for review: bootstrap hlc.gc.memprof grade

[Fergus Henderson]

On 09-Aug-2000, Peter Ross <peter.ross at miscrit.be> wrote:
> On Tue, Aug 08, 2000 at 06:14:57PM +1000, Fergus Henderson wrote:
> > On 02-Aug-2000, Peter Ross <peter.ross at miscrit.be> wrote:
> > > runtime/mercury_prof.c:
> > > runtime/mercury_prof.h:
> > >     Make decl_fptr an extern global pointer so that mercury_wrapper.c
> > >     can call fclose on it.
> > > 
> > > runtime/mercury_wrapper.c:
> > >     Call fclose on decl_fptr.
> > 
> > Why do you need to call fclose(decl_ptr) from mercury_wrapper.c?
> > There's already code to fclose(decl_ptr) in the MR_prof_finish()
> > function in runtime/mercury_prof.c.  Isn't that the right place
> > to do the close?
> > 
> If you examine the file under WinNT before the file has been closed, bad
> things happen!  So I changed to code so that fclose happened as soon as
> possible, unlike MR_prof_finish() which is called at the end of
> execution.

Hmm, I think this change may cause more problems than it solves.
In particular:
	- you didn't check the return value from fclose();
	  probably you should be calling checked_fclose() rather than fclose().
	- you've added a call to MR_fclose(),
	  but you didn't remove the old call to MR_fclose(),
	  so the file will get closed twice.  This will lead to
	  undefined behaviour...
	- if do_init_modules() is called multiple times, then
	  the file will get closed multiple times, again leading
	  to undefined behaviour.

You need to fix those problems.

There's also another minor issue: unlike the code in mercury_prof.c,
you didn't check to see whether decl_fptr is null.  That may be OK I
guess, but it might be safer to check it.

I think it would be better to abstract things a little, and do
the work from some function in mercury_prof.c which gets called
by mercury_wrapper.c, rather than doing it directly from mercury_wrapper.c.

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>  |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3        |     -- the last words of T. S. Garp.
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