Re: Use of atexit for destructors on Solaris 7.

[Charles Galambos <c dot galambos at eim dot surrey dot ac dot uk>]

Hi,

> > Since 'atexit' on solaris is function ptr it can be replaced.
> 
> Why do you think it is a function pointer? It is a proper function. It
> still can be replaced.

My mistake, its not a ptr.  Just an overly quick glace at the systems headers
and wishfull thinking on my part.

> > Is there a way I can replace the atexit function before or at least
> > early in the initilisation of static variables ?
> 
> You can provide a different version to linker. Depending on how
> exactly you arrange that, it will be used instead of the one in the C
> library. Of course, you'll also have to replace exit if you want the
> registered functions to be called...

Replacing 'atexit' and '_exithandle' functions seems to work nicely. In
one (medium-sized) program I tried, 'atexit' was called  149 times.  Only 3 or 
4
of these were calls made directly by the user.    It does put the previous
limit in perspective.

> > wasn't silently ignored, especailly as most implementations seem to
> > have a limit of the the number of times it can be called.
> 
> Why would that be good? If you have code like

If the compiler is going to do something unexpected, I'd like
to know.     I could well be relying on a destructor to close a network 
connection cleanly or something similar.  If its not going to get called, 
I'd like to know.

> MyClassC &AVar() { static MyClassC x; return x; }
> 
> it typically matters in which order these variables are initialized -
> in many cases, it does not really matter in which order/whether they
> are destroyed. In your case, what would happen if some of these global
> objects are not destroyed?

Wouldn't bother me at all in this case.   Which is why I was unaware
of the problem for so long.   The problem only bit me when I started
using gtk, and the initalisation failed on a called to 'atexit'.  All
the atexit calls were used before 'main' was even started.   It
had me completely puzzled or a while... until I fired up gtk and
did a break on atexit.  

I have a workable fix for now. I get the impression there is some work 
being done on the 'atexit' mechanism to support dynamic libraries, I
assume this limit will be removed when this is introduced ???

Thanks,

Charles.