canon-host.c disagreement (gnulib vs coreutils); zero initializers
I noticed the following disagreement between gnulib and coreutils:
--- gnulib/lib/canon-host.c 2005-05-13 23:03:57 -0700
+++ cu/lib/canon-host.c 2005-05-14 00:58:06 -0700
@@ -54,8 +54,9 @@ canon_host (char const *host)
#if HAVE_GETADDRINFO
{
-struct addrinfo hint = { 0 };
+struct addrinfo hint;
struct addrinfo *res = NULL;
+memset (&hint, 0, sizeof hint);
hint.ai_flags = AI_CANONNAME;
if (getaddrinfo (host, NULL, &hint, &res) == 0)
{
I assume that this was due to a warning from "gcc -W" about a missing
initializer. But I prefer the gnulib style: it's easier to read.
How about if we just ask people to not use "gcc -W"?
While we're on the subject, I've noticed that glibc is now using this style:
struct addrinfo hint = { 0, };
The extra comma is an indication to the reader that we know there are
missing zeros, and don't care. This style can be used for any object
in C89, e.g.:
mbstate_t initial_state = { 0, };
where we don't know whether mbstate_t is a structure, or an integer,
and the code works either way.
So, I propose that we make the following patch to gnulib, and propagate
this to coreutils:
2005-06-23 Paul Eggert <[EMAIL PROTECTED]>
* canon-host.c (canon-host): Append trailing "," to 0 in
initializer of struct addrinfo, as an indication that we don't
care how many members the structure has.
--- gnulib/lib/canon-host.c 2005-05-13 23:03:57 -0700
+++ fixed-gnulib/lib/canon-host.c 2005-06-23 16:06:21 -0700
@@ -54,7 +54,7 @@ canon_host (char const *host)
#if HAVE_GETADDRINFO
{
-struct addrinfo hint = { 0 };
+struct addrinfo hint = { 0, };
struct addrinfo *res = NULL;
hint.ai_flags = AI_CANONNAME;
if (getaddrinfo (host, NULL, &hint, &res) == 0)
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Re: canon-host.c disagreement (gnulib vs coreutils); zero initializers
Paul Eggert <[EMAIL PROTECTED]> wrote:
> I noticed the following disagreement between gnulib and coreutils:
>
> --- gnulib/lib/canon-host.c 2005-05-13 23:03:57 -0700
> +++ cu/lib/canon-host.c 2005-05-14 00:58:06 -0700
...
> I assume that this was due to a warning from "gcc -W" about a missing
> initializer. But I prefer the gnulib style: it's easier to read.
Probably.
> How about if we just ask people to not use "gcc -W"?
>
> While we're on the subject, I've noticed that glibc is now using this style:
>
> struct addrinfo hint = { 0, };
>
> The extra comma is an indication to the reader that we know there are
> missing zeros, and don't care. This style can be used for any object
> in C89, e.g.:
>
> mbstate_t initial_state = { 0, };
That's nice to know. Thanks.
> where we don't know whether mbstate_t is a structure, or an integer,
> and the code works either way.
>
> So, I propose that we make the following patch to gnulib, and propagate
> this to coreutils:
>
> 2005-06-23 Paul Eggert <[EMAIL PROTECTED]>
>
> * canon-host.c (canon-host): Append trailing "," to 0 in
> initializer of struct addrinfo, as an indication that we don't
> care how many members the structure has.
Fine. Thanks.
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Re: canon-host.c disagreement (gnulib vs coreutils); zero initializers
Paul Eggert <[EMAIL PROTECTED]> writes:
> The extra comma is an indication to the reader that we know there are
> missing zeros, and don't care. This style can be used for any object
> in C89, e.g.:
>
> mbstate_t initial_state = { 0, };
>
> where we don't know whether mbstate_t is a structure, or an integer,
> and the code works either way.
I recall some compilers complaining about a trailing ','s. Is it
really OK by C89? I'm just curious.
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Re: canon-host.c disagreement (gnulib vs coreutils); zero initializers
Simon Josefsson <[EMAIL PROTECTED]> wrote:
> Paul Eggert <[EMAIL PROTECTED]> writes:
>
>> The extra comma is an indication to the reader that we know there are
>> missing zeros, and don't care. This style can be used for any object
>> in C89, e.g.:
>>
>> mbstate_t initial_state = { 0, };
>>
>> where we don't know whether mbstate_t is a structure, or an integer,
>> and the code works either way.
>
> I recall some compilers complaining about a trailing ','s. Is it
> really OK by C89? I'm just curious.
SunOS's /bin/cc was one of the complainers,
but we've all agreed to drop support for it.
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Re: canon-host.c disagreement (gnulib vs coreutils); zero initializers
On Fri, Jun 24, 2005 at 01:16:50PM +0200, Simon Josefsson wrote: > I recall some compilers complaining about a trailing ','s. Is it > really OK by C89? I'm just curious. Oddly, it's different for array initialisers and enums, but I can't remember which is allowed and which is not. James. ___ bug-gnulib mailing list bug-gnulib@gnu.org http://lists.gnu.org/mailman/listinfo/bug-gnulib
Re: canon-host.c disagreement (gnulib vs coreutils); zero initializers
Simon Josefsson <[EMAIL PROTECTED]> writes:
> I recall some compilers complaining about a trailing ','s. Is it
> really OK by C89? I'm just curious.
Yes, it is allowed in C89.
Perhaps you're thinking of enumeration specifiers. The declaration:
enum { zero, };
is not allowed in C89. (C99 allows the trailing comma here, too --
isn't it wonderful how new features are always being added to C? :-)
Since there was agreement about the change, I installed it in gnulib
and coreutils.
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Re: canon-host.c disagreement (gnulib vs coreutils); zero initializers
Paul Eggert <[EMAIL PROTECTED]> writes:
> Simon Josefsson <[EMAIL PROTECTED]> writes:
>
>> I recall some compilers complaining about a trailing ','s. Is it
>> really OK by C89? I'm just curious.
>
> Yes, it is allowed in C89.
>
> Perhaps you're thinking of enumeration specifiers. The declaration:
>
> enum { zero, };
>
> is not allowed in C89.
Ah, indeed, I now remember that I had hit this problem with some error
value enum's in more than one of my projects. Thanks!
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