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Subject: Re: Bug in TIME function
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Date: Thu, 12 Sep 2019 11:16:27 -0700
From: Kaz Kylheku <920-082-4242 AT kylheku DOT com>
In-Reply-To: <009d01d56994$a8065040$f812f0c0$@twcny.rr.com>
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On 2019-09-12 11:05, tlake AT twcny DOT rr DOT com wrote:
> The code below returns -1. It shouldn't.

Says who?

I don't see anything in the specification which says that a null pointer 
argument is allowed:

https://pubs.opengroup.org/onlinepubs/9699919799/functions/times.html

Passing a null pointer to an ISO C or POSIX library function results in 
undefined behavior,
except where it is documented otherwise.

GNU/Linux (specifically the Glibc implementation of libc) also doesn't
document any such extension (being able to pass a null pointer to 
times).

So even in light of the goal of Cygwin providing GNU/Linux compatibility
beyond POSIX, there is no justification for supporting times(0).

> #include <sys/times.h>
> #include <stdio.h>
> 
> int main(int argc, char *argv[])
> 
> {
>   printf("return value %ld\n", (long)times((struct tms*)0));

The pointer cast is not required here; you have a prototype of
the times function in scope; the equivalent times(0) will give you
the undefined behavior you're asking for.

>   return 0;
> }

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