Re: C++ pushback

Michael Buesch
2006-04-27T13:54:29Z

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On Thursday 27 April 2006 07:37, you wrote:
> > If C++ doesn't work
> > properly for a simple and clean example like struct list_head, why
> > should we assume that it's going to work any better for more complicated
> > examples in the rest of the kernel? Whether or not some arbitrary
> > function is inlined should be totally orthogonal to adding type-checking.
>
> You misunderstood something. The struct list_head is indeed a perfect
> type to be templatized with all members inlined. C++ works properly in
> this case.

I am not sure, if you can relieably use the container_of() magic
in C++. Do you know?
I have a C++ linked list example here:
http://websvn.kde.org/trunk/extragear/security/pwmanager/pwmanager/libpwmanager/linkedlist.h?rev=421676&view=markup
It is very simple and in some points different from the kernel
linked lists. It has a separate "head" and "entry" class and it stores
a pointer to the entry (the kernel linked lists would use container_of()
instead)

> Nothing works by default. I did not say that static constructors are
> advantageous. I said that it is easy for the kernel to make static
> constructors working. Global variables should be deprecated anyway.

You are kidding. Must be...

> > Plus this would
> > break things like static spinlock initialization. How would you make
> > this work sanely for this static declaration:
> >
> > spinlock_t foo_lock = SPIN_LOCK_UNLOCKED;
> >
> > Under C that turns into (depending on config options):
> >
> > spinlock_t foo_lock = { .value = 0, .owner = NULL, (...) };
>
> I would make it exactly like this:
> #define SPIN_LOCK_UNLOCKED (spinlock_t){0,-1,whatever}
> spinlock_t foo_lock=SPIN_LOCK_UNLOCKED;
> This is easy to change. The empty structures look far more painful.

The lack of named initializers is one of the main reasons (for me)
why C++ damn sucks. Hopefully they will include them in the
next C++ standard.

--
Greetings Michael.

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