fault with calling int main( )

[Ubaid_M]

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

#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

# 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]

I see. I am not able to explain that, as it looks like the basic is in place. However, I do not know the details of your configuration (NCS version, toolchain version, etc). Can you test the sample I referred to from nRF Connect SDK 1.7.0 and using the toolchain manager so that you know the toolchain is good? That should work and does on my side.

Update: I just noticed that you add both main.c and main.cpp in your CMakeLIsts.txt:

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

you should have got a linker error if main is defined in both so it is a bit odd, but a smoking gun. (also, you probably use relative paths to make your project portable, but that is a different topic).

[Ubaid_M]

Hello  Einar Thorsrud,

Einar Thorsrud said:

You should not do this within Segger Embedded studio. Make the new file outside of it, and add it in CMakeLists.txt. Then the Segger embedded studio project is generated for you correctly.

How do I make a new file outside of it and add it in CMakeLists.txt.?

Can you kindly suggest.!

Have attached my hello_world sample project for your reference with main.cpp

7041.CPP_Test.7z

[Einar Thorsrud]

I see you only included the SES build folder, but not the folder below, which is where the relevant parts are (your source files and the CMakeLists.txt and prj.conf). Regardless, the way to add an additional C file is to either simply add a new target_sources like this (snippet from CMakeLists.txt):

target_sources(app PRIVATE src/main.cpp)
target_sources(app PRIVATE src/other_source_file.cpp)

Or you can do it like this so that app files within your src folder is added automatically:

file(GLOB app_sources src/*)
target_sources(app PRIVATE ${app_sources})

Regarding creating the file that is just a text file, so you can use your favorite editor or any other way you prefer.

Noe that after doing this you must open the project in SES again using File -> Open nRF Connect SDK Project... so that CMake runs again.

[Ubaid_M]

Hello Einar Thorsrud,

I am facing compile time issues with the inclusion of nCS files in main.cpp:

Einar Thorsrud said:

see you only included the SES build folder, but not the folder below, which is where the relevant parts are (your source files and the CMakeLists.txt and prj.conf)

I couldn't understand this.

[Einar Thorsrud]

There is no indication here of what is wrong. I have updated the hello world sample to also add a second file with a dummy class. Please test that. If you experience problems use the Toolchain manager and open Segger Embedded Studio from there so that you know it works.

Please see this sample: hello_world_cpp_additional_source_files.zip. It works well with NCS 1.7.0 and SES, and demonstrates C++ including adding a second file.

As you see from this screenshot it works well debugging in SES:

And with a UART terminal you should see this output (board name will depend on the target board you are using to test):

Hello World! nrf52840dk_nrf52840
Number is: 5
Number is now: 10

[Ubaid_M]

Hello Einar Thorsrud,

Thank you so much, This I was able to work successfully work with on VSCode.

Strangely though, as in below:

There are some errors, yet the project is building fine. If you see in the snapshot, 

#include <zephyr.h> is highlighted in red

And also there is an error: {
"resource": "/d:/sample_app/Sample/src/main.cpp",
"owner": "C/C++",
"code": "1696",
"severity": 8,
"message": "cannot open source file \"stddef.h\" (dependency of \"zephyr.h\")",
"source": "C/C++",
"startLineNumber": 7,
"startColumn": 1,
"endLineNumber": 7,
"endColumn": 20
}


How can I solve this issue..?

[Einar Thorsrud]

Ubaid_M said:

Thank you so much, This I was able to work successfully work with on VSCode.

Good to hear.

Ubaid_M said:

There are some errors, yet the project is building fine.

The error you posted in text and from the screenshot is the same. I have not been able to reproduce myself, but this looks like it is just from the intelligence in VS Code, and does not have any impact on the building of the project itself. I suggest you ignore it. Alternatively, look into the C_Cpp settings in your VS Code configuration (perhaps this thread has something useful).

[Ubaid_M]

Hello Einar Thorsrud,

Thank you the info,
Moving ahead, Request you to guide me on what are all the changes I will have to make,
So as to call the file: 
nCS\v1.7.0\zephyr\include\drivers\clock_control.h (#include clock_control.h)

In "my_class.h" file that 

Einar Thorsrud said:

Please see this sample: hello_world_cpp_additional_source_files.zip. It works well with NCS 1.7.0 and SES, and demonstrates C++ including adding a second file.

you helped me with the other day.


Thanks,

Ubaid

[Einar Thorsrud]

Hi Ubaid,

The clock control is available without the need to do any adjustments to prj.conf or similar. Simply add include statements and call the API functions you need. I suggest you refer to a relevant clock control tests to see an example.

Please make a new thread for new questions like this in the future.