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From: aotto1968 <aotto1968@t-online.de>
Newsgroups: comp.lang.c
Subject: Re: I want to use the g++ template in the "C" gcc software
Date: Thu, 12 Dec 2024 16:17:19 +0100
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On 12.12.24 11:24, David Brown wrote:
> On 12/12/2024 09:37, aotto1968 wrote:
>> Hi,
>>
>> I create a C software and there is a requirement to use the g++ template *in* the gcc.
>> I do *not* want to use all the g++ "boilerplate" like special syntax, classes etc
>> I just want to use the template.
>>
>> goal:
>>
>> 1. I already use "inline" code to replace "cpp-macro-like" syntax in the header.
>> 2. NOW I *want* to replace a "cpp-macro" which use the *data-type* as an argument with a template.
>>
>> question.
>>
>> 1. Is there a g++ switch to disable all the g++ features except of C source and template feature ?
>> 2. Is there a gcc switch to add g++-template feature into gcc ?
>> 3. is there an external software to add the c++-template feature into an existing C software ?
>>
>> thanks.
> 
> It might help if you give an example of what you are trying to achieve - it doesn't have to be valid code that can be compiled.
> 
> gcc has command-line options to disable some features of C and C++, but not like you are describing.  And C++ without classes is 
> not the same as C anyway.  But you might find you can write your code in C++ and simply not use the features you don't want to use.
> 
> If you are trying to make type-generic function-like "things" in C, then you have to use macros.  But you can use modern 
> features of C11 and C23 to make this safer and neater than in older C standards.  gcc also provides extensions that can help, if 
> you are happy writing gcc-specific code.
> 
> You should do your own googling for information, tutorials and examples here, but these links will give you some starting points:
> 
> C11 _Generic selections:
> <https://en.cppreference.com/w/c/language/generic>
> 
> C23 "typeof" and "auto" type inference:
> <https://en.cppreference.com/w/c/language/typeof>
> <https://en.cppreference.com/w/c/language/auto>
> 
> gcc extensions:
> <https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html>
> <https://gcc.gnu.org/onlinedocs/gcc/Typeof.html>
> 

Thanks for your links but I already know "feature" of gcc etc…

I still want to get better "macro" code use template like c++ has

example: (the 'cls' is a type and the `pBufferInit_T` create a type specific "inline"
-> this I want to replace with an template.

#define pBufferInit_T(pre, cls)                                                    \
   mk_inline void                                                                   \
   p##cls##Init (                                                                   \
     MK_RT_ARGS                                                                     \
     pre##cls##C##R * const loc,                                                    \
     MK_TYP  const type,                                                            \
     MK_NUM  const size                                                             \
   ) {                                                                              \
     pppBufferInit(MK_RT_CALL pre##cls##C##_X2buf(loc),size,                        \
       (MK_NUM)((*type).objsize-sizeof(pre##cls##C##R)),                            \
         offsetof(pre##cls##C##R,ils_data));                                        \
     if (type->objsig != (*pre##cls##C##_X2obj(loc)).signature) {                   \
       (*pre##cls##C##_X2obj(loc)) = MkObjInitFromType(type,true /* isLocal */);    \
     }                                                                              \
     /* ppBufferInit */                                                             \
     /* ppBufferStreamInit */                                                       \
     pp##cls##Init(MK_RT_CALL loc);                                                 \
     /* pBufferReset */                                                             \
     /* pBufferStreamReset */                                                       \
     p##cls##Reset(loc);                                                            \
   }                                                                                \