Re: Suppressing warning AC_LANG_CONFTEST

[Ralph Castain]

On Oct 12, 2010, at 2:44 PM, Eric Blake wrote:

> [please don't top-post on technical lists]

Different list, different etiquette :-)

> 
> On 10/12/2010 02:34 PM, Ralph Castain wrote:
>> Sorry for delay - was out. Since the code is rather long, I have simply 
>> attached it here.
>> 
>> Appreciate your help!
> 
> You're welcome!

Thanks again! I'll take it from here. This wasn't my configure code, but I'm 
trying my best to clean it up. Much appreciate the help.


> 
>> 
>> AC_DEFUN([EVENT_CHECK_ATTRIBUTES], [
>>  AC_LANG(C)
>>  AC_MSG_CHECKING(for __attribute__)
>> 
>>  AC_CACHE_VAL(_cv___attribute__, [
>>    AC_TRY_COMPILE(
>>      [#include <stdlib.h>
>>       /* Check for the longest available __attribute__ (since gcc-2.3) */
>>       struct foo {
>>           char a;
>>           int x[2] __attribute__ ((__packed__));
>>        };
>>      ],
> 
> Bingo.  Just as the warning said, you are missing a call to AC_LANG_PROGRAM.  
> Also, you have insufficient quoting - to get an array x[2], rather than a 
> variable name x2, you need more [] quoting.  You want to do:
> 
> 
> AC_TRY_COMPILE(
>  [AC_LANG_PROGRAM([[
>    #include <stdlib.h>
>    /* Check ... */
>    struct foo {
>      char a;
>      int x[2] __attribute__ ((__packed__));
>    };
>  ]])],
> 
> and then on with the rest of your .m4 file.
> 
>>      [],
>>      [_cv___attribute__=1],
>>      [_cv___attribute__=0],
> 
> Also, while you're at it, it might be nice to rename your cache variables to 
> have a useful prefix, rather than being in the nameless prefix namespace.
> 
>>    )
>> 
>>    if test "$_cv___attribute__" = "1" ; then
>>        AC_TRY_COMPILE(
>>          [#include <stdlib.h>
> 
> Rinse and repeat - another missing AC_LANG_PROGRAM.
> 
>>  AC_DEFINE_UNQUOTED(HAVE_ATTRIBUTE, [$_cv___attribute__],
>>                     [Whether your compiler has __attribute__ or not])
> 
> Get in the habit of proper m4 quoting:
> 
> AC_DEFINE_UNQUOTED([HAVE_ATTRIBUTE], [$_cv__attribute__], ...
> 
>> AC_DEFUN([IF_IFELSE], [
>>    AC_COMPILE_IFELSE([#if !( $1 )
>> #error "condition $1 not met"
>> choke me
>> #endif], [$2], [$3])])
> 
> Another case of missing AC_LANG_PROGRAM.
> 
>>            [AC_TRY_LINK([
>>                    #include <stdio.h>
> 
> And another.
> 
>>            AC_CACHE_CHECK([if $CC supports -xldscope],
>>                [_cv_cc_xldscope],
>>                [AC_TRY_LINK([
>>                        #include <stdio.h>
> 
> And another.
> 
> I think you can go from here on fixing this.
> 
> -- 
> Eric Blake   address@hidden    +1-801-349-2682
> Libvirt virtualization library http://libvirt.org