From: Kaz Kylheku <920-082-4242@kylheku.com>
To: cygwin@cygwin.com
Subject: Re: Bug in TIME function
Date: Thu, 12 Sep 2019 18:44:00 -0000 [thread overview]
Message-ID: <df535cb4d232ac87cc582e54fad58e01@mail.kylheku.com> (raw)
In-Reply-To: <009d01d56994$a8065040$f812f0c0$@twcny.rr.com>
On 2019-09-12 11:05, tlake@twcny.rr.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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next prev parent reply other threads:[~2019-09-12 18:16 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-12 18:16 tlake
2019-09-12 18:44 ` Kaz Kylheku [this message]
2019-09-13 0:50 ` Kaz Kylheku
2019-09-12 23:03 ` Brian Inglis
2019-09-13 11:37 ` tlake
2019-09-13 19:59 ` Wayne Davison
2019-09-13 23:05 ` Kaz Kylheku
2019-09-18 0:16 ` Brian Inglis
2019-09-16 7:30 ` Achim Gratz
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