[wwwdocs] Document __has_attribute in /gcc-5/changes.html

[wwwdocs] Document __has_attribute in /gcc-5/changes.html

[Jonathan Wakely]

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This is a slightly-modified version of Ed's patch from
https://gcc.gnu.org/ml/gcc-patches/2015-01/msg02357.html which I plan
to commit to CVS tomorrow.


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Index: changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-5/changes.html,v
retrieving revision 1.88
diff -u -r1.88 changes.html
--- changes.html	10 Mar 2015 17:34:36 -0000	1.88
+++ changes.html	11 Mar 2015 18:06:52 -0000
@@ -189,6 +189,29 @@
         of the standard directive <code>#include</code>
         and the extension <code>#include_next</code> respectively.
     </li>
+    <li>A new built-in function to detect the existence of an attribute,
+	<code>__has_attribute</code>, has been added.  The equivalent built-in
+	function <code>__has_cpp_attribute</code> was added to C++ to support
+	<a href="http://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations">
+	Feature-testing recommendations for C++</a>.
+	The function <code>__has_attribute</code> is added to all C-like
+	languages as an extension:
+<blockquote><pre>
+int
+#ifdef __has_attribute
+#  if __has_attribute(__noinline__)
+  __attribute__((__noinline__))
+#  endif
+#endif
+foo(int x);
+</pre></blockquote>
+	If an attribute exists a nonzero constant integer is returned.
+	For standardized C++ attributes a date is returned, otherwise the
+	constant returned is 1.
+	The has_attribute macros will add underscores to an attribute name
+	if necessary to resolve the name.
+	For C++11 and onwards the attribute may be scoped.
+    </li>
     <li>A new set of built-in functions for arithmetics with overflow checking
 	has been added: <code>__builtin_add_overflow</code>,
 	<code>__builtin_sub_overflow</code> and <code>__builtin_mul_overflow</code>

Re: [wwwdocs] Document __has_attribute in /gcc-5/changes.html

[Jakub Jelinek]

On Wed, Mar 11, 2015 at 06:09:11PM +0000, Jonathan Wakely wrote:
> This is a slightly-modified version of Ed's patch from
> https://gcc.gnu.org/ml/gcc-patches/2015-01/msg02357.html which I plan
> to commit to CVS tomorrow.
> 

> Index: changes.html
> ===================================================================
> RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-5/changes.html,v
> retrieving revision 1.88
> diff -u -r1.88 changes.html
> --- changes.html	10 Mar 2015 17:34:36 -0000	1.88
> +++ changes.html	11 Mar 2015 18:06:52 -0000
> @@ -189,6 +189,29 @@
>          of the standard directive <code>#include</code>
>          and the extension <code>#include_next</code> respectively.
>      </li>
> +    <li>A new built-in function to detect the existence of an attribute,

Can you please instead write built-in function-like macro?

> +	<code>__has_attribute</code>, has been added.  The equivalent built-in
> +	function <code>__has_cpp_attribute</code> was added to C++ to support
> +	<a href="http://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations">
> +	Feature-testing recommendations for C++</a>.
> +	The function <code>__has_attribute</code> is added to all C-like
> +	languages as an extension:
> +<blockquote><pre>
> +int
> +#ifdef __has_attribute
> +#  if __has_attribute(__noinline__)
> +  __attribute__((__noinline__))
> +#  endif
> +#endif
> +foo(int x);
> +</pre></blockquote>
> +	If an attribute exists a nonzero constant integer is returned.
> +	For standardized C++ attributes a date is returned, otherwise the
> +	constant returned is 1.
> +	The has_attribute macros will add underscores to an attribute name
> +	if necessary to resolve the name.
> +	For C++11 and onwards the attribute may be scoped.
> +    </li>
>      <li>A new set of built-in functions for arithmetics with overflow checking
>  	has been added: <code>__builtin_add_overflow</code>,
>  	<code>__builtin_sub_overflow</code> and <code>__builtin_mul_overflow</code>


	Jakub

Re: [wwwdocs] Document __has_attribute in /gcc-5/changes.html

[Jonathan Wakely]

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On 11/03/15 19:14 +0100, Jakub Jelinek wrote:
>On Wed, Mar 11, 2015 at 06:09:11PM +0000, Jonathan Wakely wrote:
>> This is a slightly-modified version of Ed's patch from
>> https://gcc.gnu.org/ml/gcc-patches/2015-01/msg02357.html which I plan
>> to commit to CVS tomorrow.
>>
>
>> Index: changes.html
>> ===================================================================
>> RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-5/changes.html,v
>> retrieving revision 1.88
>> diff -u -r1.88 changes.html
>> --- changes.html	10 Mar 2015 17:34:36 -0000	1.88
>> +++ changes.html	11 Mar 2015 18:06:52 -0000
>> @@ -189,6 +189,29 @@
>>          of the standard directive <code>#include</code>
>>          and the extension <code>#include_next</code> respectively.
>>      </li>
>> +    <li>A new built-in function to detect the existence of an attribute,
>
>Can you please instead write built-in function-like macro?

Yep, revised patch attached.


[-- Attachment #2: patch.txt --]
[-- Type: text/x-patch, Size: 1618 bytes --]

Index: changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-5/changes.html,v
retrieving revision 1.88
diff -u -r1.88 changes.html
--- changes.html	10 Mar 2015 17:34:36 -0000	1.88
+++ changes.html	11 Mar 2015 18:41:25 -0000
@@ -189,6 +189,30 @@
         of the standard directive <code>#include</code>
         and the extension <code>#include_next</code> respectively.
     </li>
+    <li>A new built-in function-like macro to detect the existence of an
+	attribute, <code>__has_attribute</code>, has been added.
+	The equivalent built-in macro <code>__has_cpp_attribute</code> was
+	added to C++ to support
+	<a href="http://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations">
+	Feature-testing recommendations for C++</a>.
+	The macro <code>__has_attribute</code> is added to all C-like
+	languages as an extension:
+<blockquote><pre>
+int
+#ifdef __has_attribute
+#  if __has_attribute(__noinline__)
+  __attribute__((__noinline__))
+#  endif
+#endif
+foo(int x);
+</pre></blockquote>
+	If an attribute exists a nonzero constant integer is returned.
+	For standardized C++ attributes a date is returned, otherwise the
+	constant returned is 1.
+	The has_attribute macros will add underscores to an attribute name
+	if necessary to resolve the name.
+	For C++11 and onwards the attribute may be scoped.
+    </li>
     <li>A new set of built-in functions for arithmetics with overflow checking
 	has been added: <code>__builtin_add_overflow</code>,
 	<code>__builtin_sub_overflow</code> and <code>__builtin_mul_overflow</code>

Re: [wwwdocs] Document __has_attribute in /gcc-5/changes.html

[Gerald Pfeifer]

Hi Jonathan,

On Wed, 11 Mar 2015, Jonathan Wakely wrote:
> Yep, revised patch attached.

reading this update, there are some changes I'd like to suggest.

Some (or all ;-) may be disagreeable; they all stem from me
trying to understand this update.

One question: where it refers to __has_attribute returning a
date in some cases, would it make sense to provide an example
or show the format?

By the way, gcc/doc/ does not seem to contain any documentation
of this macro?  Shouldn't that be described there?

Gerald


Index: gcc-5/changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-5/changes.html,v
retrieving revision 1.94
diff -u -r1.94 changes.html
--- gcc-5/changes.html	6 Apr 2015 12:56:40 -0000	1.94
+++ gcc-5/changes.html	7 Apr 2015 08:33:27 -0000
@@ -253,7 +253,7 @@
         of the standard directive <code>#include</code>
         and the extension <code>#include_next</code> respectively.
     </li>
-    <li>A new built-in function-like macro to detect the existence of an
+    <li>A new built-in function-like macro to determine the existence of an
 	attribute, <code>__has_attribute</code>, has been added.
 	The equivalent built-in macro <code>__has_cpp_attribute</code> was
 	added to C++ to support
@@ -270,11 +270,11 @@
 #endif
 foo(int x);
 </pre></blockquote>
-	If an attribute exists a nonzero constant integer is returned.
+	If an attribute exists, a nonzero constant integer is returned.
 	For standardized C++ attributes a date is returned, otherwise the
 	constant returned is 1.
-	The has_attribute macros will add underscores to an attribute name
-	if necessary to resolve the name.
+	The <code>has_attribute</code> macro will add underscores to an
+	attribute name if necessary to resolve the name.
 	For C++11 and onwards the attribute may be scoped.
     </li>
     <li>A new set of built-in functions for arithmetics with overflow checking

Re: [wwwdocs] Document __has_attribute in /gcc-5/changes.html

[Jakub Jelinek]

On Tue, Apr 07, 2015 at 10:38:09AM +0200, Gerald Pfeifer wrote:
> -	The has_attribute macros will add underscores to an attribute name
> -	if necessary to resolve the name.
> +	The <code>has_attribute</code> macro will add underscores to an
> +	attribute name if necessary to resolve the name.

This change looks problematic to me, as there is no has_attribute macro,
the "has_attribute macros" phrase was meant to stand for
"<code>__has_attribute</code> and <code>__has_cpp_attribute</code> macros".
For <code> I assume we want exact spelling.

	Jakub

Re: [wwwdocs] Document __has_attribute in /gcc-5/changes.html

[Jonathan Wakely]

On 07/04/15 10:38 +0200, Gerald Pfeifer wrote:
>One question: where it refers to __has_attribute returning a
>date in some cases, would it make sense to provide an example
>or show the format?

The referenced SD-6 document shows the values and format:
http://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations

I would expect that most people using the macros are going to be
referring to that document anyway.

Re: [wwwdocs] Document __has_attribute in /gcc-5/changes.html

[Gerald Pfeifer]

On Tue, 7 Apr 2015, Jakub Jelinek wrote:
> This change looks problematic to me, as there is no has_attribute macro,
> the "has_attribute macros" phrase was meant to stand for
> "<code>__has_attribute</code> and <code>__has_cpp_attribute</code> macros".
> For <code> I assume we want exact spelling.

Yes, that's a very good point.

On Tue, 7 Apr 2015, Jonathan Wakely wrote:
> The referenced SD-6 document shows the values and format:
> http://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations
> 
> I would expect that most people using the macros are going to be
> referring to that document anyway.

This is a fair point as well.

Thanks for your feedback, Jakub and Jonathan.  This is what I
just committed.

Gerald

Index: changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-5/changes.html,v
retrieving revision 1.99
diff -u -r1.99 changes.html
--- changes.html	9 Apr 2015 15:05:01 -0000	1.99
+++ changes.html	9 Apr 2015 23:26:37 -0000
@@ -262,7 +262,7 @@
         of the standard directive <code>#include</code>
         and the extension <code>#include_next</code> respectively.
     </li>
-    <li>A new built-in function-like macro to detect the existence of an
+    <li>A new built-in function-like macro to determine the existence of an
 	attribute, <code>__has_attribute</code>, has been added.
 	The equivalent built-in macro <code>__has_cpp_attribute</code> was
 	added to C++ to support
@@ -279,11 +279,12 @@
 #endif
 foo(int x);
 </pre></blockquote>
-	If an attribute exists a nonzero constant integer is returned.
+	If an attribute exists, a nonzero constant integer is returned.
 	For standardized C++ attributes a date is returned, otherwise the
 	constant returned is 1.
-	The has_attribute macros will add underscores to an attribute name
-	if necessary to resolve the name.
+	Both <code>__has_attribute</code> and
+	<code>__has_cpp_attribute</code> will add underscores to an
+	attribute name if necessary to resolve the name.
 	For C++11 and onwards the attribute may be scoped.
     </li>
     <li>A new set of built-in functions for arithmetics with overflow checking