long double (was "strtold?")

[Jeff Johnston]

Ken Werner wrote:
> On Monday 20 April 2009 23:15:24 Howland Craig D (Craig) wrote:
>   
>> Ken said:
>>     
>>> I played with the AC_TYPE_LONG_DOUBLE_WIDER macro but there are two
>>> things to consider. We would need to upgrade the autoconf version required 
>>> by newlib and introduce something like config.h (through AC_CONFIG_HEADERS). 
>>> which might pollute the name space if it get's pulled by a standard header.
>>>       
>> Jeff said:
>>     
>>> I think an executable test is required to accomplish this which can't be
>>> done in newlib due to the missing library at time of configure.
>>>       
>> Ken's former problem could easily be circumvented by writing our own
>> test
>> as he did for HAVE_LONG_DOUBLE, couldn't it?  Something like:
>>
>> cat >conftest.c <<EOF
>> #include <float.h>
>> #if DBL_MANT_DIG == LDBL_MANT_DIG  &&  LDBL_MIN_EXP == DBL_MIN_EXP  &&
>> \
>>     LDBL_MAX_EXP == DBL_MAX_EXP
>>   #define _LDBL_EQ_DBL
>>  #else
>>   #error "LDBL != DBL"
>> #endif
>> EOF
>>
>> (Of course, the #define is meaningless, but I just copied what we have
>> already and did a minimal amount of editing.  Maybe a declaration would
>> be needed in case there were any compilers that didn't like to make
>> empty objects.)
>>
>> This is not an executable test that needs the library, as float.h comes
>> from the compiler.  It just takes a compile-only pass/fail.  So I think
>> that it is viable, should we decide on this as the best alternative.
>>
>> I don't understand Ken's latter comment about name space pollution.
>> Could
>> you elaborate?
>>     
>
> This is what I had in mind. Let's assume the generated config.h contains a 
> define without an underscore prefix. If this gets pulled into a standard header 
> we would have defines that are not standardized and thus not expected by the 
> user. That might collide with user defined flags and cause side effects.
> In case we write the conftest ourselfs and manually generate the header file to 
> be included we can prepend the underscore. However, autoconf isn't my strong 
> point. : )
>
>   
This isn't a problem.  Autoconf decides what the flag will be named.  
Craig, this makes sense.
I'll work on a patch shortly.

-- Jeff J.
>> Craig
>>     
>
> Ken
>