Re: [PATCH v2 1/2] Add nmalloc and nrealloc

[Paul Eggert <eggert at cs dot ucla dot edu>]

OndÅej BÃlka wrote:
> I tried a inline function but gcc decided not to inline some of these.

Evidently you didn't use __attribute__ ((always_inline));
please try again, with that.

> +  mem = nmalloc (2, ps);

This should be nmalloc (ps, 2).  In general, if one argument is
a constant, it should be the element-size argument.  There
are several other occurrences of this.

> +  (__s == 0 || SIZE_MAX / __s < __n) ? NULL : malloc (__n * __s);	\

The check for zero element size is not necessary.  Similarly for nrealloc.
Just make it a precondition (i.e., the caller's responsibility)
that S must be nonzero.  If you're worried about bugs in the caller,
you can add a compile-time check that the element-size argument is
a constant and is positive; I expect that all the current callers will
pass that check.

> #define NMALLOC(x, t) ((t *) nmalloc (x, sizeof (t)))

I would avoid macros whose arguments are types; in this
case they're not worth the extra confusion caused by the fact that
they're not function-like.  Just have the callers invoke nmalloc,
with no NMALLOC macro.  It's easier and less error-prone to
read and write code like this:

   new_global = nmalloc (new_nalloc, sizeof *new_global);

than code like this:

   new_global = NMALLOC (new_nalloc, struct link_map *);

particularly in cases, such as here, where the type is a
pointer.