Re: [Qemu-devel] [PATCH] use qemu_malloc and friends consistently

[David Turner <digit@google.com>]

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On Tue, Jun 2, 2009 at 10:58 PM, Paul Brook <paul@codesourcery.com> wrote:

> > I think you're afraid of the following case instead:
> >
> > foo*  ptr;
> > ptr = QEMU_MEW(bar);   =>   compiler will complain that 'ptr' is not a
> bar*
> >
> >But this is not possible with the first version anyway.
>
> Rubbish. Works perfectly.
>

I think there is a misunderstanding here, what I mean is that:

#define  QEMU_NEW(ptr)  (ptr) = malloc(sizeof(*ptr))

foo*  ptr;
QEMU_NEW(ptr);

Will never try to allocate sizeof(bar) bytes, anyway.
The rest is taste/personal preference, and there is no point fighting about
it.

As I said, I just want to say that abort() on qemu_malloc(0) is not the
shiny good thing
some people are expecting, and that there are better ways to fight potential
developer errors.


>
> cat  test.c <<EOF
> #include <stdlib.h>
> #define QEMU_NEW(type) (type*)malloc(sizeof(type))
> typedef struct { int x; } foo;
> typedef struct { double y; } bar;
> int main(int argc, char **argv)
> {
>  foo *ptr = QEMU_NEW(bar);
>  return 0;
> }
> EOF
> gcc test.c
> test.c: In function ‘main’:
> test.c:7: initialization from incompatible pointer type
>
> Paul
>

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