Why can't you add a new class in Segger ?

RE: Why can't you add a new class in Segger ?

butch — Sat, 03 Jun 2017 11:43:08 GMT

The question whether to use C or C++ is subjective, opinionated. You can mix C and C++, but it takes some learning and work. The main thing you need to understand is C++ "name mangling" (the two different calling conventions) and when to wrap C code that is being compiled by the C++ compiler in "extern "C" {}" wrapper. Nordic doesn't "officially" support C++ but much of their code is C++ compatible. I use the C++ compiler with the Nordic SDK, but I don't use all of the SDK, and in a few places I made a few minor hacks to the SDK, and I need to ignore a few warnings from the C++ compiler. So maybe I get C++'s advantage of OOP, but it comes with the cost of dealing with mixed C/C++.

RE: Why can't you add a new class in Segger ?

Lola — Fri, 02 Jun 2017 12:19:03 GMT

Ok thanks, sorry for asking. I just keep wondering if writing a production code only in C is something people usually do.

RE: Why can't you add a new class in Segger ?

Jørgen Holmefjord — Fri, 02 Jun 2017 11:42:18 GMT

Our SDK does not support C++ beyond the header guards in the drivers/libraries, and as far as I know this will not change in the near future. If you want to use C++, you need to spend the time it takes to convert the project into C++. There are much resources online that can help you solve any issues you could encounter. This is not a Nordic-specific issue, you would have encountered the same issues converting any C project into supporting C++.

RE: Why can't you add a new class in Segger ?

Lola — Fri, 02 Jun 2017 11:11:49 GMT

Thanks a lot, I have actually seen this page and tried it all, nothing helps. My question is, if you want to write a complex embedded application, you probably would like to use C++ to make it more powerful( arn't you? ) and you will always have C code from the drivers, and the libraries. So at some point you would like to include a c++ file to your code. To do that I did as you suggested, changed main to be cpp , so I can include cpp. Then everyone says you can't do that. So what CAN I do to use C++ ? :)

RE: Why can't you add a new class in Segger ?

Jørgen Holmefjord — Fri, 02 Jun 2017 11:08:11 GMT

Yes, if you have C code in the main.c file, you cannot simply change it to .cpp. See for instance this page for more information about calling C++ functions from C.

RE: Why can't you add a new class in Segger ?

Lola — Fri, 02 Jun 2017 11:02:26 GMT

Hi, if I change the main to cpp I get 250 errors, some of them are :

'->' cannot appear in a constant-expression
'&' cannot appear in a constant-expression
a cast to a type other than an integral or enumeration type cannot appear in a constant-expression

They are coming from C files used by Nordic (drivers and libraries). The project was an example project from SDK, and I'v added other things to it.

I asked some people about it on the net, and they said I can't just mixed C and C++ files, so for example:

main.cpp
#include "flash.h"
int main(void){}

Will produce errors because I include C file in C++ file , where the C might not be properly writen for C++.

Some of the errors comes from lines like this :

NRF_GPIOTE_TASKS_OUT_0     = offsetof(NRF_GPIOTE_Type, TASKS_OUT[0]), /**< Out task 0.*/

RE: Why can't you add a new class in Segger ?

Jørgen Holmefjord — Fri, 02 Jun 2017 09:38:05 GMT

Could you post the errors? Did you setup the project from scratch or following the SES tutorial blog post?

RE: Why can't you add a new class in Segger ?

Lola — Thu, 01 Jun 2017 13:26:30 GMT

Thanks, if i create a new file main.cpp with the exact same content, the project will give 206 errors on compilation, I am not sure anymore how to work with this Segger, all the obvious things I used to just do, here I always encounter a wall.

RE: Why can't you add a new class in Segger ?

Jørgen Holmefjord — Thu, 01 Jun 2017 09:11:49 GMT

If you want the C++ class from Test.h to be used in main, you need to make main a .cpp file, otherwise it will compile using the C compiler.

RE: Why can't you add a new class in Segger ?

Lola — Thu, 01 Jun 2017 09:01:42 GMT

Thanks, I know it should work but Segger on mac is always hard, nothing just works and I guess I have to "enable" something. I have many files, this is one of them. In the main file (the main is not cpp, it's a c file ) I include this file ( Test.h) . Should the main become cpp also ? will it then work with the C files ?

RE: Why can't you add a new class in Segger ?

Jørgen Holmefjord — Thu, 01 Jun 2017 08:51:32 GMT

I tested with your header file and main.cpp, it compile fine. It seems this issue usually is caused by not compiling using C++, or by Circular dependency. Do you include this in main.cpp, or do you have multiple files in your project?