va_list ARM changes

[Iain Buclaw]

On 31 August 2012 13:05, Johannes Pfau <nospam at example.com> wrote:
> Am Fri, 31 Aug 2012 12:49:37 +0100
> schrieb Iain Buclaw <ibuclaw at ubuntu.com>:
>
>> Part of where you are going wrong is that 'va_arg (va_list, TypeInfo,
>> void*)' should only be used when the static type is indeterminable.
>> This is typically only for structs and classes.  All basic types
>> should go through the normal va_arg template functions - these
>> actually get expanded intrinsically by the gcc backend and *do* the
>> right thing, even for your float example.
>
> OK, then everything is working as expected.
>>
>> Now that is not to say that you can't use 'va_arg (va_list, TypeInfo,
>> void*)' for basic types, but you do need to be aware of type
>> promotions when it comes to va_args. :-)
>>
>> Eg:
>>
>> void main()
>> {
>>   test2("", cast(float)3.45f, "TestTest");  // float is promoted to
>> double when passed as a vararg.
>> }
>>
>> void test2(string input, ...)
>> {
>>   double f;
>>   string s;
>>   va_list list;
>>   va_start(list, input);
>>   va_arg(list, typeid(typeof(f)), &f);
>>   va_arg(list, typeid(typeof(s)), &s);
>>   va_end(list);
>>   writefln("%s %s", f, s);
>> }
>>
>>
>> And you'll see that test2() in your paste works.
>>
> Still doesn't work for me, but if basic types should not be used with
> that va_arg overload and as the templated version works fine anyway it
> doesn't matter.
>

Boo!

I should have really brought my ARM device with me so I could test
this... unfortunately I left it at home 300 miles away.


-- 
Iain Buclaw

*(p < e ? p++ : p) = (c & 0x0f) + '0';