fault with calling int main( )

Question

Hello,

I modified a sample app "blinky" on segger, to include main.cpp instead of main.c
Then when I built, I got a compile time error stating in main.cpp "void main(void)" should be changed to "int main( )"
I changed and it compiled successfully.

Now when I am running it on the board, the execution is not entering "int main( )" rather the execution is straight away entering fault_s.S, as in the screenshot:

Kindly help me in understanding why this is happening so and how I can get the execution to return to "int main( )" ..?

PS. I am using blinky sample app on segger, only changes I made is
- Excluded main.c from the build
- Added main.cpp (Attaching for your reference)
- Added main.cpp in CMakeLists.txt (Attaching for your reference)

It is building successfully.

main.cpp

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#include "stdio.h"
#include "stdint.h"
/**** 1. Demonstration On dynamic allocation  ****/
class Sample
{
  Sample* cPtr;
  public:
  Sample()
  {
    printf("ctor called \n");
    cPtr = new Sample();
  }
  
  ~Sample()
  {
    printf("dtor called \n");
    delete cPtr;
    cPtr = nullptr;
  }
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#include "stdio.h"
#include "stdint.h"

/**** 1. Demonstration On dynamic allocation  ****/
class Sample
{
  Sample* cPtr;
  public:
  Sample()
  {
    printf("ctor called \n");
    cPtr = new Sample();
  }
  
  ~Sample()
  {
    printf("dtor called \n");
    delete cPtr;
    cPtr = nullptr;
  }

};

/*
 * Copyright (c) 2016 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

//#include <zephyr.h>
//#include <device.h>
//#include <devicetree.h>
//#include <drivers/gpio.h>

///* 1000 msec = 1 sec */
//#define SLEEP_TIME_MS   1000

///* The devicetree node identifier for the "led0" alias. */
//#define LED0_NODE DT_ALIAS(led0)

//#if DT_NODE_HAS_STATUS(LED0_NODE, okay)
//#define LED0	DT_GPIO_LABEL(LED0_NODE, gpios)
//#define PIN	DT_GPIO_PIN(LED0_NODE, gpios)
//#define FLAGS	DT_GPIO_FLAGS(LED0_NODE, gpios)
//#else
///* A build error here means your board isn't set up to blink an LED. */
//#error "Unsupported board: led0 devicetree alias is not defined"
//#define LED0	""
//#define PIN	0
//#define FLAGS	0
//#endif
       void func(void)
       {
        Sample obj;
       }

int main(void)
{
	const struct device *dev;
	bool led_is_on = true;
	int ret;

        func();

	//dev = device_get_binding(LED0);
	//if (dev == NULL) {
	//	return;
	//}

	//ret = gpio_pin_configure(dev, PIN, GPIO_OUTPUT_ACTIVE | FLAGS);
	//if (ret < 0) {
	//	return;
	//}

	//while (1) {
	//	gpio_pin_set(dev, PIN, (int)led_is_on);
	//	led_is_on = !led_is_on;
	//	k_msleep(SLEEP_TIME_MS);
	//}

        return 0;
}

CMakeLists.txt

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# SPDX-License-Identifier: Apache-2.0
cmake_minimum_required(VERSION 3.20.0)
find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
project(blinky)
target_sources(app PRIVATE D:/CPP_Test/cpp_files/main.cpp src/main.c)
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# SPDX-License-Identifier: Apache-2.0

cmake_minimum_required(VERSION 3.20.0)
find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
project(blinky)

target_sources(app PRIVATE D:/CPP_Test/cpp_files/main.cpp src/main.c)

Einar Thorsrud · Accepted Answer

If you add a new folder that you need to include from, then you need to do this. This is only the case for include paths you add yourself, though (so your folders with your files in them). 
 This is not the case if you for instance add a library that already exists in the nRF Connect SDK. For any library/driver/etc. that is part of the nRF Connect SDK this is done for you, so you only need to enable it in your prj.conf. Finding it can be difficult, but here I suggest you refer to a relevant sample for what you want to do. You can also search the list of all configuration options .

fault with calling int main( )

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