musl - Re: alx-0029r5 - Restore the traditional realloc(3) specification

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Message-ID: <lhuzfdt40s5.fsf@oldenburg.str.redhat.com>
Date: Fri, 27 Jun 2025 18:17:14 +0200
From: Florian Weimer <fweimer@...hat.com>
To: Alejandro Colomar <alx@...nel.org>
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Subject: Re: alx-0029r5 - Restore the traditional realloc(3) specification

* Alejandro Colomar:

> I think everybody agrees that glibc's calloc(3) is conforming to C11,
> and it behaves like my proposal suggests.
>
> 	alx@...ian:~/tmp$ cat c.c 
> 	#include <stdio.h>
> 	#include <stdlib.h>
>
> 	int
> 	main(void)
> 	{
> 		printf("%p\n", calloc(0, 42));
> 		perror("calloc(0, 42)");
>
> 		printf("%p\n", calloc(42, 0));
> 		perror("calloc(42, 0)");
>
> 		printf("%p\n", calloc(0, 0));
> 		perror("calloc(0, 0)");
> 	}
> 	alx@...ian:~/tmp$ gcc c.c 
> 	alx@...ian:~/tmp$ ./a.out 
> 	0x564b188332a0
> 	calloc(0, 42): Success
> 	0x564b188338d0
> 	calloc(42, 0): Success
> 	0x564b18833d00
> 	calloc(0, 0): Success
>
> In any case, I've improved the wording to be more explicit about it.
> See alx-0029r6.

I think the wording still allows calloc (42, 0) to fail with EINVAL (or
some other error code) because 0 is not a valid object size.

Thanks,
Florian

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