Problem with compiling C++ code for nRF52820

[db_lw]

Hi,

I tried to build the ble_app_uart example for nRF52820/s140. In my project I need to use C++ modules.

My usual approach that worked so far:

• Take an example project
• Rename the main.c to main.cpp
• Replace line 381-385
  

  ble_gap_phys_t const phys =
  {
      .tx_phys = BLE_GAP_PHY_AUTO,
      .rx_phys = BLE_GAP_PHY_AUTO,
  };

• Compile with -std=gnu+11.

Oddly this doesn't work with the nRF52820 example and I always get the following error when compiling.

In file included from ../nrf5_sdk/modules/nrfx/mdk/nrf.h:192,
                 from D:\Development\wDALI2_BT_Switch\wdali-2-bt-button\firmware\ble_app_uart_pca10100e_s140\main.cpp:55:
../nrf5_sdk/modules/nrfx/mdk/compiler_abstraction.h:193:60: error: expected constructor, destructor, or type conversion before '(' token
../nrf5_sdk/modules/nrfx/mdk/compiler_abstraction.h:232:5: note: in expansion of macro 'NRF_STATIC_ASSERT'
../nrf5_sdk/modules/nrfx/mdk/nrf_erratas.h:48:1: note: in expansion of macro 'NRF_MDK_VERSION_ASSERT_AT_LEAST'

When I do the same thing with the ble_app_uart example for nRF52840/s140 it compiles just fine with C++.

Does anyone have an idea how to fix this problem and why it only occurs when compiling for nRF52820?

Thanks in advance.

[db_lw]

I was able to trace the problem down to the header file nrf_gpio.h. It seems like it doesn't build with C++ for nRF52820 because of the include in line 65. But I'm not sure how to solve this properly.

#if defined(NRF52820_XXAA)
#include <nrf_erratas.h>
#endif

[Edvin]

Hello,

Please search for

extern "C"

In your project. See how some files have this:

    #ifdef __cplusplus
         }  /* extern "C" */
      }  /* namespace std */
    #endif /* __cplusplus */
    
    
    
    ...
    
    
    #ifdef __cplusplus
    #ifndef __STDARG_NO_EXPORTS
      using ::std::va_list;
    #endif
  #endif /* __cplusplus */

Try to include that in nrf_erratas.h.

Best regards,

Edvin

[db_lw]

Hello,

thanks for your answer.

Did you mean to put the extern "C" in nrf_erratas.h like below?

Because I tried that and I am still getting the same error on building.

#ifdef __cplusplus
extern "C" {
#endif

...

#ifdef __cplusplus
}
#endif

[Edvin]

What does the nrf_erratas.h file look like now? And what error message do you get? Can you paste it even though it is the same as before?

I don't have the C++ setup that you have. If I did, I would have tested this myself, but unfortunately, I don't.

Best regards,

Edvin

[db_lw]

Right now I am just using the ble_app_uart for pca10100e/s140 example (nRF5 SDK 17.0.2) with no additions other than the following to make it build with the C++ compiler.

• Rename the main.c to main.cpp
• Replace line 381-385
   

  ble_gap_phys_t const phys =
  {
      .tx_phys = BLE_GAP_PHY_AUTO,
      .rx_phys = BLE_GAP_PHY_AUTO,
  };

• Compile with -std=gnu+11.

This is my edited nrf_erratas.h file: 

nrf_erratas.h

This is the compilation error I get:

In file included from ../nrf5_sdk/modules/nrfx/mdk/nrf.h:192,
                 from D:\Development\wDALI2_BT_Switch\wdali-2-bt-button\firmware\ble_app_uart_pca10100e_s140\main.cpp:55:
../nrf5_sdk/modules/nrfx/mdk/compiler_abstraction.h:193:60: error: expected constructor, destructor, or type conversion before '(' token
../nrf5_sdk/modules/nrfx/mdk/compiler_abstraction.h:232:5: note: in expansion of macro 'NRF_STATIC_ASSERT'
../nrf5_sdk/modules/nrfx/mdk/nrf_erratas.h:52:1: note: in expansion of macro 'NRF_MDK_VERSION_ASSERT_AT_LEAST'