Re: Interface with C codes

[Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP>]

On 2014-10-19, Anh Vo <anhvofrcaus@gmail.com> wrote:
> On Saturday, October 18, 2014 11:33:32 AM UTC-7, Stephen Leake wrote:
>> Anh Vo <anhvofrcaus@gmail.com> writes:
>> > On Friday, October 17, 2014 4:22:15 PM UTC-7, Anh Vo wrote:
>> >>  
>> >> char *  bootStringToStruct (char * bootString,  BOOT_PARAMS * pBootParams); 
>> >  
>> > Should this one work?
>> >
>> > function Boot_String_To_Type (
>> >            Boot_String : Interfaces.C.Strings.chars_ptr;
>> >            Boot_Params : Boot_Parameter_Type_Access) 
>> >                              return Interfaces.C.Strings.chars_ptr; 
>> > pragma Import (C, Boot_String_To_Type, "bootStringToStruct");
>> 
>> Looks good. but give -fdump-ada-spec a try.
>
> Yes, I tried and the result is below.
>
> function bootStringToStruct (bootString : Interfaces.C.Strings.chars_ptr;
>                                 pBootParams : access BOOT_PARAMS)
>                                    return Interfaces.C.Strings.chars_ptr;
> pragma Import (CPP, bootStringToStruct,  "_Z18bootStringToStructPcP11BOOT_PARAMS");
>
> Why was "_Z18bootStringToStructPcP11BOOT_PARAMS" generated for third parameter of pragma Import? I thought it should be "bootStringToStruct".
>

It's known as a mangled symbol and is required with C++ (notice your
latter example is using "CPP" and not "C" on the pragma Import).

The "Name mangling in C++" section of the following might be useful:

http://en.wikipedia.org/wiki/Name_mangling

Simon.

-- 
Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
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