Re: replacement getaddrinfo not working properly

[Aharon Robbins]

Hi. Thanks for tracking this down. I will look into modifying things along
the lines you suggest.

Arnold

In article <address@hidden> you write:
>Hi,
>
>It seems that adding AC_USE_SYSTEM_EXTENSIONS to configure.ac
>will always cause _POSIX_PTHREAD_SEMANTICS and _TANDEM_SOURCE to
>be defined (at least that is the case for autoconf version 2.61 on my
>linux FC6 host).  From /usr/share/autoconf/autoconf/specific.m4:
>
>   # AC_USE_SYSTEM_EXTENSIONS
>   # ------------------------
>   # Enable extensions on systems that normally disable them,
>   # typically due to standards-conformance issues.
>   AC_DEFUN([AC_USE_SYSTEM_EXTENSIONS],
>   [
>     AC_BEFORE([$0], [AC_COMPILE_IFELSE])
>     AC_BEFORE([$0], [AC_RUN_IFELSE])
>
>     AC_REQUIRE([AC_GNU_SOURCE])
>     AC_REQUIRE([AC_AIX])
>     AC_REQUIRE([AC_MINIX])
>
>     AH_VERBATIM([__EXTENSIONS__],
>   [/* Enable extensions on Solaris.  */
>   #ifndef __EXTENSIONS__
>   # undef __EXTENSIONS__
>   #endif
>   #ifndef _POSIX_PTHREAD_SEMANTICS
>   # undef _POSIX_PTHREAD_SEMANTICS
>   #endif
>   #ifndef _TANDEM_SOURCE
>   # undef _TANDEM_SOURCE
>   #endif])
>     AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
>       [ac_cv_safe_to_define___extensions__],
>       [AC_COMPILE_IFELSE(
>         [AC_LANG_PROGRAM([
>   #     define __EXTENSIONS__ 1
>            AC_INCLUDES_DEFAULT])],
>         [ac_cv_safe_to_define___extensions__=yes],
>         [ac_cv_safe_to_define___extensions__=no])])
>     test $ac_cv_safe_to_define___extensions__ = yes &&
>       AC_DEFINE([__EXTENSIONS__])
>     AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
>     AC_DEFINE([_TANDEM_SOURCE])
>   ])
>
>As you can see, this defines _POSIX_PTHREAD_SEMANTICS and _TANDEM_SOURCE
>unconditionally.
>
>As a result, this logic in io.c to decide whether to include
>missing_d/getaddrinfo.h is not working as intended:
>
>   #ifdef _TANDEM_SOURCE
>   #include <arpa/inet.h>
>   #include <netdb.h>
>   #else
>   #ifdef HAVE_GETADDRINFO
>   #include <netdb.h>
>   #else
>   #include "missing_d/getaddrinfo.h"
>   #endif
>   #endif
>
>Because _TANDEM_SOURCE is defined, there is never any chance
>of including missing_d/getaddrinfo.h.
>
>This causes compilation errors on systems that do not supply getaddrinfo.
>
>I'm not certain of the best fix.  Why is it necessary to test
>for _TANDEM_SOURCE at all in this spot?  It seems that the only
>difference is whether to include <arpa/inet.h>.  Couldn't configure.ac
>just test whether this header file exists (and similarly for netdb.h),
>and just include them unconditionally if they exist (without caring
>about _TANDEM_SOURCE)?
>
>Regards,
>Andy
>
>


-- 
Aharon (Arnold) Robbins --- Pioneer Consulting Ltd.     arnold AT skeeve DOT com
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