Re: [PATCH 4/8] xalloc: new function xreallocarray

[Paul Eggert]

On 4/21/21 17:18, Bruno Haible wrote:
> xnmalloc and XNMALLOC take 2 arguments, whereas xreallocarray takes 3
> arguments. It is often possible to express a function with a simple
> interface as a special case of a more complex function. If, in many
> use-cases, the simpler function is sufficient, users should not be
> forced to understand the more complex function.

Good point. Also, xnmalloc enables better static checking, as it has 
__attribute__ ((__malloc__)), __attribute__ ((__malloc__ (free, 1))), 
and  __attribute__ ((__returns_nonnull__)), whereas xreallocarray 
doesn't have these.

I noticed this when converting GNU diffutils to use ximalloc etc, and 
this this convinced me to add xinmalloc, by installing the attached 
patch. I plan to use this in GNU diffutils and probably other apps.


Should we change xreallocarray to always return nonnull? We could then 
add __attribute__ ((__returns_nonnull__)) to its declaration. This might 
help performance and/or static checking a bit. The only downside I can 
see is that xreallocarray's semantics would differ a bit more from glibc 
reallocarray's.

0001-xalloc-new-function-xinmalloc.patch
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