Programming nRF52 DK in C++ in Segger Embedded Studio

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

Bhaveesh — Fri, 05 Feb 2021 10:26:13 GMT

Thanks, it works with sdk v17.0.2.

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

ovrebekk — Thu, 04 Feb 2021 08:19:13 GMT

Can you try the example in SDK v17.0.2?

There were some changes in how the RAM segments are set up between SDK v17.0.0 and v17.0.2, and I expect this to be the problem in your case.

Best regards
Torbjørn

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

Bhaveesh — Wed, 03 Feb 2021 12:54:18 GMT

Hi ovrebekk

Thanks for your sample example.

When I try to compile this example. Linker throws following error.

1> Linking ble_app_uart_pca10056_s140.elf
C:\Users\Kumarbhv\Downloads\nRF5_SDK_17.0.0_9d13099\modules\nrfx\mdk/ses_startup_nrf_common.s:110: undefined reference to `__RAM_segment_end__'

Can you please help me with that?

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

ovrebekk — Tue, 12 Jan 2021 07:34:22 GMT

You welcome Usman, good to hear you got it working 🙂

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Mon, 11 Jan 2021 10:39:20 GMT

--- edit ---

After I removed static from static void idle_state_handle(void), it all compiled perfectly.

Thanks again. :)

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Mon, 11 Jan 2021 10:32:19 GMT

Hi Shiv.

Thank you so much for this helpful guide. It will definitely help me A LOT when I mix my C and C++ code.

Regards,

Usman

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Mon, 11 Jan 2021 10:01:51 GMT

Hi Torbjørn.

Thank you so much for the help.

I took your code and made mine similar to it. It turns out I was misunderstanding the instructions all along, and now the code compiles. Just one little problem left.

Whenever I include the app_idle_state_handle() in the code, it fails to compile, says "undefined reference to `app_idle_state_handle'", even though I know the functioned is fully defined in both .c and .h files. I don't know why it does this. But when I remove the function call from main.cpp, all works well.

If I call the same function in the .c file, it works perfectly. If you can provide any guidance with that, that would be great, but it's not a major issue, since it wasn't useful to me anyway.

Best regards,

Usman

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

Shivek — Fri, 08 Jan 2021 17:21:34 GMT

Hi Usman,

You can wrap your cpp code with extern C and I have found one reference for you to make it understandable.

Read this link here and I hope this would be helpful for you.

-Shiv

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

ovrebekk — Fri, 08 Jan 2021 13:16:28 GMT

Hi Usman

I did the same exercise myself based on the ble_app_uart example to illustrate how it can be done:
devzone.nordicsemi.com/.../261622_5F00_ble_5F00_app_5F00_uart.zip

Basically I copy the entirety of the main.c file into the separate C file (ble_app.c).

Essentially the only thing I put in the ble_app.h file is the prototype of any function that needs to be called from main.cpp. Everything else I leave in the ble_app.c file, to avoid this being pulled into main.cpp when you include the header file.

If you try to follow the same approach I expect you should get the example to compile.

Best regards
Torbjørn

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Thu, 07 Jan 2021 10:16:05 GMT

Hi Torbjørn

Please see https://gofile.io/d/l955b2

Its basically the ble_app_uart__saadc_timer_driven__scan_mode example

Thank you so much for your help.

Regards,

Usman

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

ovrebekk — Thu, 07 Jan 2021 08:29:27 GMT

Hi Usman

Are you able to share your project with me so I can try it out?

I can make the case private if you don't want to share it in public.

Best regards
Torbjørn

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Tue, 05 Jan 2021 06:09:38 GMT

Hi Torbjørn

After a few attempts, I finally managed to get this working

[quote userid="94615" url="~/f/nordic-q-a/69579/programming-nrf52-dk-in-c-in-segger-embedded-studio/286967#286967"]And so I tried to compile them with just printf( )[/quote]

and it compiled.

So I put in my original code in these files, and now it returns the same old error.

expected constructor, destructor, or type conversion before '(' token

How could it be that it is compiling the simple .c file inside the .cpp file perfectly, but as soon as I add my other code to the .c file, it fails to compile? The my code in original .c file itself was compiling and working perfectly.

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

ovrebekk — Wed, 30 Dec 2020 09:56:34 GMT

Hi Usman

Good point, I forgot to mention this. Every header file that defines functions that you need to include in a C++ file needs to use the extern "C" header, otherwise they won't be visible to the C++ linker.

If you open any of the standard header files in the SDK you can spot this.

Essentially they will have the following somewhere at the top of the header file (after any includes but before any defines or function prototypes):

#ifdef __cplusplus
extern "C" {
#endif

And then the following at the bottom of the file (before the final #endif):

#ifdef __cplusplus
}
#endif

Best regards
Torbjørn

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Wed, 30 Dec 2020 09:44:23 GMT

Hi Torbjørn

Yes, I tried that as well. But no good.

And so I tried to compile them with just printf( ) in it and here's what my files look like:

main.cpp:

#include "c_file.h"

int main(void)
{
    func();
}

c_file.h:

#ifndef CFile_H
#define CFILE_H

#include <stdbool.h>
#include <stdint.h>
#include <string.h>

int func();

#endif

c_file.c:

#ifndef CFile_C
#define CFILE_C

#include <stdbool.h>
#include <stdint.h>
#include <string.h>

int func()
{
    printf("this c file");
    return 0;
}

#endif

And it gives me this error: undefined reference to `func()'

Am I doing something wrong here?

Regards

Usman

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

ovrebekk — Wed, 30 Dec 2020 09:30:32 GMT

Hi Usman

Did you move all the instance definitions at the top of main.c into the separate file?

They should look something like this:

BLE_NUS_DEF(m_nus, NRF_SDH_BLE_TOTAL_LINK_COUNT);                                   /**< BLE NUS service instance. */
NRF_BLE_GATT_DEF(m_gatt);                                                           /**< GATT module instance. */
NRF_BLE_QWR_DEF(m_qwr);                                                             /**< Context for the Queued Write module.*/
BLE_ADVERTISING_DEF(m_advertising);                                                 /**< Advertising module instance. */

These macros will not compile in C++, and they will also have to be available to the rest of the BLE code if you move this into a separate file.

Best regards
Torbjørn

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Tue, 29 Dec 2020 05:01:51 GMT

Hi Torbjørn.

Thanks for the correction. I did exactly as you told, but it still gives the same old errors

[quote userid="94615" url="~/f/nordic-q-a/69579/programming-nrf52-dk-in-c-in-segger-embedded-studio/285764#285764"]

Capture

ImgBB

[/quote]

I even tried removing ALL code from the cpp file and just put a printf( ) just to see if that works, but doesn't compile either. At this point, I think its more of a configuration issue, but I could be wrong.

Any guidance would be highly appreciated.

Regards

Usman

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

ovrebekk — Tue, 22 Dec 2020 13:43:39 GMT

Hi Usman

First off you shouldn't include a C file from another C file. Instead you need to create a header file (c_file.h essentially) that contains the function prototypes for the functions in c_file.c that you need to access, and include this header file only from main.c.

Also, in this file I would suggest splitting the code into a couple of independent functions for doing things such as:

- Initializing the Bluetooth stack
- Starting advertising
- Sending or receiving data from a connected device
- anything else that your application needs to do over Bluetooth

In the end your main file could look something like this:

static void on_ble_event(app_ble_event_t *event)
{
    switch(event->type)
    {
        case APP_BLE_EVT_DATA_RECEIVED:
            break;
        case APP_BLE_EVT_CONNECTED:
            break;
            
        // And any other events you need to send back to the main function
    }            
}

int main(void)
{
    app_ble_initialize(/*Arguments here*/);
    app_ble_set_callback(on_ble_event);
    
    app_ble_start_advertising();
    
    // Main loop
    while(1)
    {
        // If you have something to do repeatedly in the main loop in c_file.c then you can call it from here:
        app_ble_execute();
    }
}

Hopefully this makes sense?
Please note that my pseudo code suggestion above is not the only way to do it, but I think it's a good way to move the details of configuring and managing the Bluetooth stack into a separate file (I think it's a good idea to do this even if you don't need to compile your project for C++).

Best regards
Torbjørn

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Tue, 22 Dec 2020 06:17:30 GMT

Hi Torbjørn

[quote userid="2116" url="~/f/nordic-q-a/69579/programming-nrf52-dk-in-c-in-segger-embedded-studio/286007#286007"] you move the BLE functionality out of the main file and into a separate C file (that you can then call from the main.cpp file)[/quote]

I did this, now my code is like this, but it shows the exact same errors.

If I remove #include "c_file.c" from the top, and mainx() in the main function, then it compiles. But now with them. What am I doing wrong here?

#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include "c_file.c"

int main(void)
{
    mainx();
}

Thanks, and regards,

Usman

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Mon, 21 Dec 2020 11:21:13 GMT

Hi Torbjørn.

Thanks for the insight. It makes a lot of sense, since I'm using ble_app_uart example as a base.

So what I should do is, make a main.cpp file, put my non BLE code into it, rename the old main.c file into something else, and call the .c file in my main.cpp file?

Best regards,

Usman

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

ovrebekk — Mon, 21 Dec 2020 10:33:04 GMT

Hi Usman

Which example are you using?

Unfortunately many of the API's in the SDK, including several of the BLE API's, don't support C++. As such the standard example will not build in C++, unless you move the BLE functionality out of the main file and into a separate C file (that you can then call from the main.cpp file).

Best regards
Torbjørn

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Fri, 18 Dec 2020 08:44:12 GMT

Hi Torbjørn. Thanks for the information.

I did just that and got a plethora of errors.

https://ibb.co/nD623Tz

How do I fix these?

Best regards

Usman

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

ovrebekk — Fri, 18 Dec 2020 08:22:01 GMT

Hi Usman

This will happen if you try to include a C++ header file in a C file, since the C file will be compiled using the C compiler.

Any source file where you want to access C++ libraries will itself need to be a C++ file, which means you have to make the main.c file into a main.cpp file if you want to call C++ libraries from main.

Best regards
Torbjørn

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Thu, 17 Dec 2020 09:29:52 GMT

Hi Torbjørn, thanks for pointing that out.

When I compile, it gives this error where the object class is defined

unknown type name 'class'

What am I missing here?
Regards
Usman

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

ovrebekk — Thu, 17 Dec 2020 09:21:25 GMT

Hi Usman

Any .cpp file should automatically be compiled using the C++ compiler, while any .c files will be compiled by the C compiler, so it should be possible to mix and match C and C++ code.

There might be library files in the SDK that will not compile in C++, because they use language features only available in C, but it should be possible to get around this by using C++ for your sensor libraries only.

Have you tried to integrate any .cpp files in your project?

If yes, did you face any issues?

Best regards
Torbjørn

RE: Programming nRF52 DK in C++ in Segger Embedded Studio

usmanmehmood55 — Wed, 16 Dec 2020 16:03:59 GMT

I do know C++, but the question is about something else.

Thanks.