[boost] Request for rationale

From: Mike Tegtmeyer (tegtmeye_at_[hidden])
Date: 2007-11-02 16:32:03

I am often asked why shared_ptr always uses the custom deleter even when 
the pointer argument is zero. I know it is safe to delete a NULL pointer 
so this works with delete but it would seem that if the user is giving a 
custom deleter, then they are probably doing something else. ie

//will crash if fread returns 0
shared_ptr<FILE> foo(fread("foo.txt","r"),fclose);

This is an easy screw-up for most new folks and the docs don't really 
explicitly point out this (I think) non-obvious behavior.

One can obviously wrap the deleter with a check among numerous other 
things but I'm curious what the rationale was since this won't work "out 
of the box" with C APIs.  Can someone point me to the dialog discussing 
the design decision for this behavior so I can pass it along?

Thanks,
Mike