[C++-11] User defined literals

Ed Smith-Rowland 3dw4rd@verizon.net
Thu Oct 27 19:15:00 GMT 2011


On 10/26/2011 03:38 PM, Jason Merrill wrote:
> On 10/26/2011 02:00 AM, Ed Smith-Rowland wrote:
>> The patch was bootstrapped and regtested on x86_64-linux-gnu.
>
> Really?  I ran into a warning about the unused "suffix" parameter to 
> interpret_integer.  So I've fixed that error.  I also added a couple 
> of comments, and implemented the change to check_literal_operator_args 
> that I wondered about a while back.  And checked it all in.
>
> But we aren't quite done, I think: I notice that the lookup of 
> operators doesn't match what's in 2.14.8.  For instance, I don't think 
> this should be accepted:
>
> double operator"" _foo (long long unsigned);
> double d = 1.2_foo;
I'm on it.
It looks like these incorrectly pass too:

int operator"" _char(char);
int operator"" _wchar_t(wchar_t);
int operator"" _char16_t(char16_t);
int operator"" _char32_t(char32_t);

int cwc = 'c'_wchar_t;
int cc16 = 'c'_char16_t;
int cc32 = 'c'_char32_t;

int wcc = L'c'_char;
int wcc16 = L'c'_char16_t;
int wcc31 = L'c'_char32_t;

etc.

I'm guessing pointer conversion errors would prevent something similar 
happening to raw and string operators but I'll check and repair.
>
> The lookup described in 2.14.8 involves looking through the overload 
> set for a particular signature before doing normal overload resolution.
>
> Also, we don't need to worry about argument-dependent lookup for these 
> operators, since none of the arguments can have associated namespaces. 
> So I think we can use lookup_name rather than 
> lookup_function_nonclass, only look it up once in 
> cp_userdef_numeric_literal, and then only build one call depending on 
> the contents of the overload set.
>
> Jason



More information about the Gcc-patches mailing list