Complete Simple Examples of "Pragma Import (CPP,...) With Qualifiers?

Complete Simple Examples of "Pragma Import (CPP,...) With Qualifiers?

[Ruby_Tuesday@gmail.com]

The only thing I am seeing in some code are statements such as the one below without any qualifiers:

PRAGMA IMPORT (Convention=> CPP, Entity => "My_Test" ,External_Name => "My_Test");

Are there other versions of this that I could see? What about C++ qualifiers,  members in classes, and namespaces how are they referenced in the pragma?

Thank you,
Ruby

Re: Complete Simple Examples of "Pragma Import (CPP,...) With Qualifiers?

[Lucretia]

On Wednesday, 11 September 2019 19:16:04 UTC+1, Ruby_T...@gmail.com  wrote:
> The only thing I am seeing in some code are statements such as the one below without any qualifiers:
> 
> PRAGMA IMPORT (Convention=> CPP, Entity => "My_Test" ,External_Name => "My_Test");
> 
> Are there other versions of this that I could see? What about C++ qualifiers,  members in classes, and namespaces how are they referenced in the pragma?

That is all there is, only bringing in the c++ methods. There used to be a constructor and destructor, but they got rid of those for some unknown reason.

Re: Complete Simple Examples of "Pragma Import (CPP,...) With Qualifiers?

[godunko]

On Wednesday, September 11, 2019 at 9:16:04 PM UTC+3, Ruby_T...@gmail.com wrote:
> 
> Are there other versions of this that I could see? What about C++ qualifiers,  members in classes, and namespaces how are they referenced in the pragma?
> 
You need to use pragma CPP_Constructor to bind constructors. External_Names are always mangled names, used by linker. Class fields may be mapped to record, but you need to control memory layout carefully. So, direct binding to C++ is not so simple and it is very complicated to support it. I personally prefer to create C wrappers around C++ classes when possible, more code need to be produced, but you don't need to take care about low level C++ stuff mapping and update binding each time API/ABI changed or porting to another C++ compiler.

Re: Complete Simple Examples of "Pragma Import (CPP,...) With Qualifiers?

[Ruby_Tuesday@gmail.com]

> > On Wednesday, September 11, 2019 at 9:16:04 PM UTC+3, Ruby_T...@gmail.com 
>> wrote:
> > 
> > Are there other versions of this that I could see? What about C++ qualifiers,  members in classes, and namespaces how are they referenced in the pragma?
> > 

On Thursday, September 12, 2019 at 12:50:44 AM UTC-5, god...@adacore.com wrote:
>   
>                                           Class fields may be mapped to 
> record, but you need to control memory layout carefully. So, direct binding to 
> C++ is not so simple and it is very complicated to support it.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Does anyone have an intuitive tutorial on how to accomplish this?

How does the memory layout differ for different things pointed to by the pragma's "External_Name"? Basically, with a simple but complete example how is the Ada code written?

Thank you,
Ruby

Re: Complete Simple Examples of "Pragma Import (CPP,...) With Qualifiers?

[Roger]

On Thursday, September 12, 2019 at 4:16:04 AM UTC+10, Ruby_T...@gmail.com wrote:
> The only thing I am seeing in some code are statements such as the one below without any qualifiers:
> 
> PRAGMA IMPORT (Convention=> CPP, Entity => "My_Test" ,External_Name => "My_Test");
> 
> Are there other versions of this that I could see? What about C++ qualifiers,  members in classes, and namespaces how are they referenced in the pragma?
> 
> Thank you,
> Ruby

I tried doing something similar sometime ago on my Mac but eventually gave up due to continuing difficulties and finally solved my problem by writing some short wrapper programs. 

Re: Complete Simple Examples of "Pragma Import (CPP,...) With Qualifiers?

[Roger]

On Thursday, September 12, 2019 at 4:16:04 AM UTC+10, Ruby_T...@gmail.com wrote:
> The only thing I am seeing in some code are statements such as the one below without any qualifiers:
> 
> PRAGMA IMPORT (Convention=> CPP, Entity => "My_Test" ,External_Name => "My_Test");
> 
> Are there other versions of this that I could see? What about C++ qualifiers,  members in classes, and namespaces how are they referenced in the pragma?
> 
> Thank you,
> Ruby

I tried doing something similar sometime ago on my Mac but eventually gave up due to continuing difficulties and finally solved my problem by writing some short  functions in C++ with Ada wrappers.