[PATCH] Enable XSI extensions by default

[PATCH] Enable XSI extensions by default

[Sebastian Huber]

This test program

  #include <strings.h>

  int f(int i)
  {
    return ffs(i);
  }

resulted in the follwing GCC warning

  warning: implicit declaration of function 'ffs' [-Wimplicit-function-declaration]

This is not the case for glibc and FreeBSD.  On FreeBSD __XSI_VISBLE is
by default defined to 700.  Do this also on Newlib.

Signed-off-by: Sebastian Huber <sebastian.huber@embedded-brains.de>
---
 newlib/libc/include/sys/features.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/newlib/libc/include/sys/features.h b/newlib/libc/include/sys/features.h
index c9133af57..4102903bc 100644
--- a/newlib/libc/include/sys/features.h
+++ b/newlib/libc/include/sys/features.h
@@ -96,13 +96,13 @@ extern "C" {
  * _GNU_SOURCE
  * 	All of the above plus GNU extensions
  *
  * _BSD_SOURCE (deprecated by _DEFAULT_SOURCE)
  * _SVID_SOURCE (deprecated by _DEFAULT_SOURCE)
  * _DEFAULT_SOURCE (or none of the above)
- * 	POSIX-1.2008 with BSD and SVr4 extensions
+ * 	POSIX-1.2008 with BSD, SVr4 and XSI extensions
  */
 
 #ifdef _GNU_SOURCE
 #undef _ATFILE_SOURCE
 #define	_ATFILE_SOURCE		1
 #undef	_DEFAULT_SOURCE
@@ -131,12 +131,14 @@ extern "C" {
 
 #if defined(_DEFAULT_SOURCE)
 #undef _POSIX_SOURCE
 #define	_POSIX_SOURCE		1
 #undef _POSIX_C_SOURCE
 #define	_POSIX_C_SOURCE		200809L
+#undef _XOPEN_SOURCE
+#define	_XOPEN_SOURCE		700
 #endif
 
 #if !defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE) && \
   ((!defined(__STRICT_ANSI__) && !defined(_ANSI_SOURCE)) || \
    (_XOPEN_SOURCE - 0) >= 500)
 #define	_POSIX_SOURCE		1
@@ -197,13 +199,13 @@ extern "C" {
  *	SUSv2 XSI extensions; enabled with _XOPEN_SOURCE >= 500.
  *
  * __XSI_VISIBLE >= 600
  *	SUSv3 XSI extensions; enabled with _XOPEN_SOURCE >= 600.
  *
  * __XSI_VISIBLE >= 700
- *	SUSv4 XSI extensions; enabled with _XOPEN_SOURCE >= 700.
+ *	SUSv4 XSI extensions; enabled by default, or with _XOPEN_SOURCE >= 700.
  *
  * __ISO_C_VISIBLE >= 1999
  * 	ISO C99; enabled with gcc -std=c99 or newer (on by default since GCC 5),
  * 	any version of C++, or with _ISOC99_SOURCE, _POSIX_C_SOURCE >= 200112L,
  * 	or _XOPEN_SOURCE >= 600.
  *
-- 
2.12.3

Re: [PATCH] Enable XSI extensions by default

[Corinna Vinschen]

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On Aug 25 07:29, Sebastian Huber wrote:
> This test program
> 
>   #include <strings.h>
> 
>   int f(int i)
>   {
>     return ffs(i);
>   }
> 
> resulted in the follwing GCC warning
> 
>   warning: implicit declaration of function 'ffs' [-Wimplicit-function-declaration]
> 
> This is not the case for glibc and FreeBSD.  On FreeBSD __XSI_VISBLE is
> by default defined to 700.  Do this also on Newlib.

Sounds right to me, but I'd like to have Yaakov's input as our
local header standarizer :)

Yaakov?


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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Re: [PATCH] Enable XSI extensions by default

[Yaakov Selkowitz]

On 2017-08-25 00:29, Sebastian Huber wrote:
> This test program
> 
>   #include <strings.h>
> 
>   int f(int i)
>   {
>     return ffs(i);
>   }
> 
> resulted in the follwing GCC warning
> 
>   warning: implicit declaration of function 'ffs' [-Wimplicit-function-declaration]

Then the guards on ffs need to be fixed to match glibc.

> This is not the case for glibc and FreeBSD.  On FreeBSD __XSI_VISBLE is
> by default defined to 700.  Do this also on Newlib.

Nak.  glibc does *not* enable XSI extensions by default.

-- 
Yaakov

Re: [PATCH] Enable XSI extensions by default

[Corinna Vinschen]

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On Aug 25 14:18, Yaakov Selkowitz wrote:
> On 2017-08-25 00:29, Sebastian Huber wrote:
> > This test program
> > 
> >   #include <strings.h>
> > 
> >   int f(int i)
> >   {
> >     return ffs(i);
> >   }
> > 
> > resulted in the follwing GCC warning
> > 
> >   warning: implicit declaration of function 'ffs' [-Wimplicit-function-declaration]
> 
> Then the guards on ffs need to be fixed to match glibc.

glibc man page claims

   _POSIX_C_SOURCE >= 200809L
       || /* Glibc since 2.19: */ _DEFAULT_SOURCE
       || /* Glibc versions <= 2.19: */ _BSD_SOURCE ||
   _SVID_SOURCE

> > This is not the case for glibc and FreeBSD.  On FreeBSD __XSI_VISBLE is
> > by default defined to 700.  Do this also on Newlib.
> 
> Nak.  glibc does *not* enable XSI extensions by default.
> 
> -- 
> Yaakov


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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[PATCH] include: fix ffs, fls guards

[Yaakov Selkowitz]

Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
---
 newlib/libc/include/strings.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/newlib/libc/include/strings.h b/newlib/libc/include/strings.h
index 35fcdc092..122f2fcd6 100644
--- a/newlib/libc/include/strings.h
+++ b/newlib/libc/include/strings.h
@@ -50,12 +50,14 @@ void	 bzero(void *, size_t);					/* LEGACY */
 #if __BSD_VISIBLE
 void	 explicit_bzero(void *, size_t);
 #endif
-#if __XSI_VISIBLE
+#if __MISC_VISIBLE || __POSIX_VISIBLE < 200809 || __XSI_VISIBLE >= 700
 int	 ffs(int) __pure2;
 #endif
-#if __BSD_VISIBLE
+#if __GNU_VISIBLE
 int	 ffsl(long) __pure2;
 int	 ffsll(long long) __pure2;
+#endif
+#if __BSD_VISIBLE
 int	 fls(int) __pure2;
 int	 flsl(long) __pure2;
 int	 flsll(long long) __pure2;
-- 
2.14.1

Re: [PATCH] include: fix ffs, fls guards

[Corinna Vinschen]

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On Aug 29 12:58, Yaakov Selkowitz wrote:
> Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
> ---
>  newlib/libc/include/strings.h | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/newlib/libc/include/strings.h b/newlib/libc/include/strings.h
> index 35fcdc092..122f2fcd6 100644
> --- a/newlib/libc/include/strings.h
> +++ b/newlib/libc/include/strings.h
> @@ -50,12 +50,14 @@ void	 bzero(void *, size_t);					/* LEGACY */
>  #if __BSD_VISIBLE
>  void	 explicit_bzero(void *, size_t);
>  #endif
> -#if __XSI_VISIBLE
> +#if __MISC_VISIBLE || __POSIX_VISIBLE < 200809 || __XSI_VISIBLE >= 700
>  int	 ffs(int) __pure2;
>  #endif
> -#if __BSD_VISIBLE
> +#if __GNU_VISIBLE
>  int	 ffsl(long) __pure2;
>  int	 ffsll(long long) __pure2;
> +#endif
> +#if __BSD_VISIBLE
>  int	 fls(int) __pure2;
>  int	 flsl(long) __pure2;
>  int	 flsll(long long) __pure2;
> -- 
> 2.14.1

ACK, please push.


Thanks,
Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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Re: [PATCH] include: fix ffs, fls guards

[Joel Sherrill]

We had two targets (or1k and epiphany) for RTEMS that were
using gcc 4.9.x with the current newlib snapshot. They
were giving no prototype warnings for flsl(). The targets
on gcc 7.2 were not giving that warning on the same code.

Would you expect this to fix that?

--joel

On 8/29/2017 2:15 PM, Corinna Vinschen wrote:
> On Aug 29 12:58, Yaakov Selkowitz wrote:
>> Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
>> ---
>>   newlib/libc/include/strings.h | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/newlib/libc/include/strings.h b/newlib/libc/include/strings.h
>> index 35fcdc092..122f2fcd6 100644
>> --- a/newlib/libc/include/strings.h
>> +++ b/newlib/libc/include/strings.h
>> @@ -50,12 +50,14 @@ void	 bzero(void *, size_t);					/* LEGACY */
>>   #if __BSD_VISIBLE
>>   void	 explicit_bzero(void *, size_t);
>>   #endif
>> -#if __XSI_VISIBLE
>> +#if __MISC_VISIBLE || __POSIX_VISIBLE < 200809 || __XSI_VISIBLE >= 700
>>   int	 ffs(int) __pure2;
>>   #endif
>> -#if __BSD_VISIBLE
>> +#if __GNU_VISIBLE
>>   int	 ffsl(long) __pure2;
>>   int	 ffsll(long long) __pure2;
>> +#endif
>> +#if __BSD_VISIBLE
>>   int	 fls(int) __pure2;
>>   int	 flsl(long) __pure2;
>>   int	 flsll(long long) __pure2;
>> -- 
>> 2.14.1
> 
> ACK, please push.
> 
> 
> Thanks,
> Corinna
> 

--joel