GNU bug report logs - #14830
[PATCH] * configure.ac (HAVE_W32): Avoid nested functions

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Package: emacs;

Reported by: Peter Rosin <peda <at> lysator.liu.se>

Date: Mon, 8 Jul 2013 22:51:02 UTC

Severity: normal

Tags: patch

Done: Eli Zaretskii <eliz <at> gnu.org>

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Report forwarded to bug-gnu-emacs <at> gnu.org:
bug#14830; Package emacs. (Mon, 08 Jul 2013 22:51:02 GMT) Full text and rfc822 format available.
Acknowledgement sent to Peter Rosin <peda <at> lysator.liu.se>:
New bug report received and forwarded. Copy sent to bug-gnu-emacs <at> gnu.org. (Mon, 08 Jul 2013 22:51:02 GMT) Full text and rfc822 format available.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Peter Rosin <peda <at> lysator.liu.se>
To: bug-gnu-emacs <at> gnu.org
Subject: [PATCH] * configure.ac (HAVE_W32): Avoid nested functions
Date: Tue, 09 Jul 2013 00:49:43 +0200

diff --git a/ChangeLog b/ChangeLog
index 220cffb..03011cf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2013-07-09  Peter Rosin <peda <at> lysator.liu.se>  (tiny change>
+
+	* configure.ac (HAVE_W32): Avoid nested functions (the second
+	argument of AC_LANG_PROGRAM is expanded inside a function).
+
 2013-07-08  Magnus Henoch <magnus.henoch <at> gmail.com> (tiny change)

 	* configure.ac (HAVE_IMAGEMAGICK): Check on NS also (Bug#14798).
diff --git a/configure.ac b/configure.ac
index 3830ee3..1188f1b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1632,10 +1632,10 @@ fi

 if test "${opsys}" = "mingw32"; then
   AC_MSG_CHECKING([whether Windows API headers are recent enough])
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
      #include <windows.h>
-     #include <usp10.h>]],
-   [[void test(PIMAGE_NT_HEADERS pHeader)
+     #include <usp10.h>
+     void test(PIMAGE_NT_HEADERS pHeader)
      {PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);}]])],
    [emacs_cv_w32api=yes
     HAVE_W32=yes],
--
1.7.9
Information forwarded to bug-gnu-emacs <at> gnu.org:
bug#14830; Package emacs. (Tue, 09 Jul 2013 02:42:02 GMT) Full text and rfc822 format available.

Message #8 received at 14830 <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Peter Rosin <peda <at> lysator.liu.se>
Cc: 14830 <at> debbugs.gnu.org
Subject: Re: bug#14830: [PATCH] * configure.ac (HAVE_W32): Avoid nested
 functions
Date: Tue, 09 Jul 2013 05:41:07 +0300

> Date: Tue, 09 Jul 2013 00:49:43 +0200
> From: Peter Rosin <peda <at> lysator.liu.se>
> 
> diff --git a/ChangeLog b/ChangeLog
> index 220cffb..03011cf 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,8 @@
> +2013-07-09  Peter Rosin <peda <at> lysator.liu.se>  (tiny change>
> +
> +	* configure.ac (HAVE_W32): Avoid nested functions (the second
> +	argument of AC_LANG_PROGRAM is expanded inside a function).
> +
>  2013-07-08  Magnus Henoch <magnus.henoch <at> gmail.com> (tiny change)
> 
>  	* configure.ac (HAVE_IMAGEMAGICK): Check on NS also (Bug#14798).
> diff --git a/configure.ac b/configure.ac
> index 3830ee3..1188f1b 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1632,10 +1632,10 @@ fi
> 
>  if test "${opsys}" = "mingw32"; then
>    AC_MSG_CHECKING([whether Windows API headers are recent enough])
> -  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
> +  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
>       #include <windows.h>
> -     #include <usp10.h>]],
> -   [[void test(PIMAGE_NT_HEADERS pHeader)
> +     #include <usp10.h>
> +     void test(PIMAGE_NT_HEADERS pHeader)
>       {PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);}]])],
>     [emacs_cv_w32api=yes
>      HAVE_W32=yes],

Sorry, I don't follow: what is the problem with the current code?
Information forwarded to bug-gnu-emacs <at> gnu.org:
bug#14830; Package emacs. (Tue, 09 Jul 2013 06:28:01 GMT) Full text and rfc822 format available.

Message #11 received at 14830 <at> debbugs.gnu.org (full text, mbox):

From: Peter Rosin <peda <at> lysator.liu.se>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 14830 <at> debbugs.gnu.org
Subject: Re: bug#14830: [PATCH] * configure.ac (HAVE_W32): Avoid nested
 functions
Date: Tue, 09 Jul 2013 08:27:33 +0200

On 2013-07-09 04:41, Eli Zaretskii wrote:
>> Date: Tue, 09 Jul 2013 00:49:43 +0200
>> From: Peter Rosin <peda <at> lysator.liu.se>
>>
>> diff --git a/ChangeLog b/ChangeLog
>> index 220cffb..03011cf 100644
>> --- a/ChangeLog
>> +++ b/ChangeLog
>> @@ -1,3 +1,8 @@
>> +2013-07-09  Peter Rosin <peda <at> lysator.liu.se>  (tiny change>
>> +
>> +	* configure.ac (HAVE_W32): Avoid nested functions (the second
>> +	argument of AC_LANG_PROGRAM is expanded inside a function).
>> +
>>  2013-07-08  Magnus Henoch <magnus.henoch <at> gmail.com> (tiny change)
>>
>>  	* configure.ac (HAVE_IMAGEMAGICK): Check on NS also (Bug#14798).
>> diff --git a/configure.ac b/configure.ac
>> index 3830ee3..1188f1b 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -1632,10 +1632,10 @@ fi
>>
>>  if test "${opsys}" = "mingw32"; then
>>    AC_MSG_CHECKING([whether Windows API headers are recent enough])
>> -  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
>> +  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
>>       #include <windows.h>
>> -     #include <usp10.h>]],
>> -   [[void test(PIMAGE_NT_HEADERS pHeader)
>> +     #include <usp10.h>
>> +     void test(PIMAGE_NT_HEADERS pHeader)
>>       {PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);}]])],
>>     [emacs_cv_w32api=yes
>>      HAVE_W32=yes],
> 
> Sorry, I don't follow: what is the problem with the current code?
> 

AC_LANG_PROGRAM([[
     #include <windows.h>
     #include <usp10.h>]],
   [[void test(PIMAGE_NT_HEADERS pHeader)
     {PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);}]])

is expanded into the following program (enhanced whitespace):

#include <windows.h>
#include <usp10.h>

int
main ()
{
  void test(PIMAGE_NT_HEADERS pHeader)
  {
    PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);
  }
  ;
  return 0;
}

My fixed version with AC_LANG_SOURCE will not emit the main() function
and thus avoids nested functions and instead generates this source (again
with enhanced whitespace):

#include <windows.h>
#include <usp10.h>

void
test(PIMAGE_NT_HEADERS pHeader)
{
  PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);
}

The background is that when trying to configure with an unsupported
compiler, MSVC in this case, it errors out with "the Windows API
headers are too old to support this build", which is a bogus error
message.

Agreed, it doesn't really change anything for supported configurations,
but being able to nest functions has nothing to do with the test at
hand.

Cheers,
Peter
Information forwarded to bug-gnu-emacs <at> gnu.org:
bug#14830; Package emacs. (Tue, 09 Jul 2013 06:54:02 GMT) Full text and rfc822 format available.

Message #14 received at 14830 <at> debbugs.gnu.org (full text, mbox):

From: Peter Rosin <peda <at> lysator.liu.se>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 14830 <at> debbugs.gnu.org
Subject: Re: bug#14830: [PATCH] * configure.ac (HAVE_W32): Avoid nested
 functions
Date: Tue, 09 Jul 2013 08:53:30 +0200

On 2013-07-09 08:27, Peter Rosin wrote:
> On 2013-07-09 04:41, Eli Zaretskii wrote:
>>> Date: Tue, 09 Jul 2013 00:49:43 +0200
>>> From: Peter Rosin <peda <at> lysator.liu.se>
>>>
>>> diff --git a/ChangeLog b/ChangeLog
>>> index 220cffb..03011cf 100644
>>> --- a/ChangeLog
>>> +++ b/ChangeLog
>>> @@ -1,3 +1,8 @@
>>> +2013-07-09  Peter Rosin <peda <at> lysator.liu.se>  (tiny change>
>>> +
>>> +	* configure.ac (HAVE_W32): Avoid nested functions (the second
>>> +	argument of AC_LANG_PROGRAM is expanded inside a function).
>>> +
>>>  2013-07-08  Magnus Henoch <magnus.henoch <at> gmail.com> (tiny change)
>>>
>>>  	* configure.ac (HAVE_IMAGEMAGICK): Check on NS also (Bug#14798).
>>> diff --git a/configure.ac b/configure.ac
>>> index 3830ee3..1188f1b 100644
>>> --- a/configure.ac
>>> +++ b/configure.ac
>>> @@ -1632,10 +1632,10 @@ fi
>>>
>>>  if test "${opsys}" = "mingw32"; then
>>>    AC_MSG_CHECKING([whether Windows API headers are recent enough])
>>> -  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
>>> +  AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
>>>       #include <windows.h>
>>> -     #include <usp10.h>]],
>>> -   [[void test(PIMAGE_NT_HEADERS pHeader)
>>> +     #include <usp10.h>
>>> +     void test(PIMAGE_NT_HEADERS pHeader)
>>>       {PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);}]])],
>>>     [emacs_cv_w32api=yes
>>>      HAVE_W32=yes],
>>
>> Sorry, I don't follow: what is the problem with the current code?
>>
> 
> AC_LANG_PROGRAM([[
>      #include <windows.h>
>      #include <usp10.h>]],
>    [[void test(PIMAGE_NT_HEADERS pHeader)
>      {PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);}]])
> 
> is expanded into the following program (enhanced whitespace):
> 
> #include <windows.h>
> #include <usp10.h>
> 
> int
> main ()
> {
>   void test(PIMAGE_NT_HEADERS pHeader)
>   {
>     PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);
>   }
>   ;
>   return 0;
> }
> 
> My fixed version with AC_LANG_SOURCE will not emit the main() function
> and thus avoids nested functions and instead generates this source (again
> with enhanced whitespace):
> 
> #include <windows.h>
> #include <usp10.h>
> 
> void
> test(PIMAGE_NT_HEADERS pHeader)
> {
>   PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);
> }
> 
> The background is that when trying to configure with an unsupported
> compiler, MSVC in this case, it errors out with "the Windows API
> headers are too old to support this build", which is a bogus error
> message.
> 
> Agreed, it doesn't really change anything for supported configurations,
> but being able to nest functions has nothing to do with the test at
> hand.

Hmm, the below variant is perhaps clearer?

It expands into:

#include <windows.h>
#include <usp10.h>

int
main ()
{
  PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);
  return 0;
}

Cheers,
Peter


diff --git a/ChangeLog b/ChangeLog
index 220cffb..3ba3093 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2013-07-09  Peter Rosin <peda <at> lysator.liu.se>  (tiny change>
+
+       * configure.ac (HAVE_W32): Avoid nested functions (the second
+       argument of AC_LANG_PROGRAM is already expanded inside a function).
+
 2013-07-08  Magnus Henoch <magnus.henoch <at> gmail.com> (tiny change)

        * configure.ac (HAVE_IMAGEMAGICK): Check on NS also (Bug#14798).
diff --git a/configure.ac b/configure.ac
index 3830ee3..ddfef68 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1635,8 +1635,7 @@ if test "${opsys}" = "mingw32"; then
   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
      #include <windows.h>
      #include <usp10.h>]],
-   [[void test(PIMAGE_NT_HEADERS pHeader)
-     {PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);}]])],
+   [[PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader)]])],
    [emacs_cv_w32api=yes
     HAVE_W32=yes],
    emacs_cv_w32api=no)
--
1.7.9
Information forwarded to bug-gnu-emacs <at> gnu.org:
bug#14830; Package emacs. (Tue, 09 Jul 2013 06:57:01 GMT) Full text and rfc822 format available.

Message #17 received at 14830 <at> debbugs.gnu.org (full text, mbox):

From: Andreas Schwab <schwab <at> suse.de>
To: Peter Rosin <peda <at> lysator.liu.se>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 14830 <at> debbugs.gnu.org
Subject: Re: bug#14830: [PATCH] * configure.ac (HAVE_W32): Avoid nested
 functions
Date: Tue, 09 Jul 2013 08:56:13 +0200

Peter Rosin <peda <at> lysator.liu.se> writes:

> My fixed version with AC_LANG_SOURCE will not emit the main() function
> and thus avoids nested functions and instead generates this source (again
> with enhanced whitespace):
>
> #include <windows.h>
> #include <usp10.h>
>
> void
> test(PIMAGE_NT_HEADERS pHeader)
> {
>   PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);
> }

You should instead remove the function.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab <at> suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
Information forwarded to bug-gnu-emacs <at> gnu.org:
bug#14830; Package emacs. (Tue, 09 Jul 2013 07:18:02 GMT) Full text and rfc822 format available.

Message #20 received at 14830 <at> debbugs.gnu.org (full text, mbox):

From: Andreas Schwab <schwab <at> suse.de>
To: Peter Rosin <peda <at> lysator.liu.se>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 14830 <at> debbugs.gnu.org
Subject: Re: bug#14830: [PATCH] * configure.ac (HAVE_W32): Avoid nested
 functions
Date: Tue, 09 Jul 2013 09:17:16 +0200

Peter Rosin <peda <at> lysator.liu.se> writes:

> #include <windows.h>
> #include <usp10.h>
>
> int
> main ()
> {
>   PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);

You need to declare pHeader somewhere.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab <at> suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
Information forwarded to bug-gnu-emacs <at> gnu.org:
bug#14830; Package emacs. (Tue, 09 Jul 2013 08:08:02 GMT) Full text and rfc822 format available.

Message #23 received at 14830 <at> debbugs.gnu.org (full text, mbox):

From: Peter Rosin <peda <at> lysator.liu.se>
To: Andreas Schwab <schwab <at> suse.de>
Cc: Eli Zaretskii <eliz <at> gnu.org>, 14830 <at> debbugs.gnu.org
Subject: Re: bug#14830: [PATCH] * configure.ac (HAVE_W32): Avoid nested
 functions
Date: Tue, 09 Jul 2013 10:07:28 +0200

On 2013-07-09 09:17, Andreas Schwab wrote:
> Peter Rosin <peda <at> lysator.liu.se> writes:
> 
>> #include <windows.h>
>> #include <usp10.h>
>>
>> int
>> main ()
>> {
>>   PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);
> 
> You need to declare pHeader somewhere.

Big sigh. Thanks for catching...

Cheers,
Peter

diff --git a/ChangeLog b/ChangeLog
index 220cffb..3ba3093 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2013-07-09  Peter Rosin <peda <at> lysator.liu.se>  (tiny change>
+
+       * configure.ac (HAVE_W32): Avoid nested functions (the second
+       argument of AC_LANG_PROGRAM is already expanded inside a function).
+
 2013-07-08  Magnus Henoch <magnus.henoch <at> gmail.com> (tiny change)

        * configure.ac (HAVE_IMAGEMAGICK): Check on NS also (Bug#14798).
diff --git a/configure.ac b/configure.ac
index 3830ee3..bb140a8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1635,8 +1635,8 @@ if test "${opsys}" = "mingw32"; then
   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
      #include <windows.h>
      #include <usp10.h>]],
-   [[void test(PIMAGE_NT_HEADERS pHeader)
-     {PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);}]])],
+   [[PIMAGE_NT_HEADERS pHeader;
+     PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader)]])],
    [emacs_cv_w32api=yes
     HAVE_W32=yes],
    emacs_cv_w32api=no)
--
1.7.9
Reply sent to Eli Zaretskii <eliz <at> gnu.org>:
You have taken responsibility. (Tue, 09 Jul 2013 18:09:02 GMT) Full text and rfc822 format available.
Notification sent to Peter Rosin <peda <at> lysator.liu.se>:
bug acknowledged by developer. (Tue, 09 Jul 2013 18:09:02 GMT) Full text and rfc822 format available.

Message #28 received at 14830-done <at> debbugs.gnu.org (full text, mbox):

From: Eli Zaretskii <eliz <at> gnu.org>
To: Peter Rosin <peda <at> lysator.liu.se>
Cc: schwab <at> suse.de, 14830-done <at> debbugs.gnu.org
Subject: Re: bug#14830: [PATCH] * configure.ac (HAVE_W32): Avoid nested
 functions
Date: Tue, 09 Jul 2013 21:07:44 +0300

> Date: Tue, 09 Jul 2013 10:07:28 +0200
> From: Peter Rosin <peda <at> lysator.liu.se>
> CC: Eli Zaretskii <eliz <at> gnu.org>, 14830 <at> debbugs.gnu.org
> 
> On 2013-07-09 09:17, Andreas Schwab wrote:
> > Peter Rosin <peda <at> lysator.liu.se> writes:
> > 
> >> #include <windows.h>
> >> #include <usp10.h>
> >>
> >> int
> >> main ()
> >> {
> >>   PIMAGE_SECTION_HEADER pSection = IMAGE_FIRST_SECTION(pHeader);
> > 
> > You need to declare pHeader somewhere.
> 
> Big sigh. Thanks for catching...

Thanks, committed as trunk revision 113349.
bug archived. Request was from Debbugs Internal Request <help-debbugs <at> gnu.org> to internal_control <at> debbugs.gnu.org. (Wed, 07 Aug 2013 11:24:03 GMT) Full text and rfc822 format available.
This bug report was last modified 11 years and 321 days ago.

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