RPI Console output variable contents

Question

Hello,

I am successfully running a modified version of the device integration example for Raspberry Pi 3B+ and in the DeviceDriver.c file I have added some code which I want to get console outputs to my SSH terminal on the variable values.

I can see any hardcoded message using either printf or EwPrint but when i try to print the value of any variable (char in my example below) the program halts and a segmentation fault is reported in the console output.

Example code inserted into the DeviceDriver_ProcessData function:

		printf("Read\n");
		ID = frame.can_id;
		if (ID > 0) 
		{ 
			char B = '5';
			EwPrint(B); 
		} 
		else 
		{ 
			EwPrint("no message ID\n"); 
		}

Console output:

From the above code I would be expecting the program not to halt and the console to display:

Read

5

Can anyone help with getting variable contents onto the console from a devicedriver C file?

 

Answer 1

Hello,

it seems that you did not use EwPrint() or printf() correctly. The first parameter expects a pointer to the format string and not a single character - please see the declaration of these functions.

Please try

char B = '5';
printf( "%c\n", B );

Does it work?

Best regards,

Manfred

Comments

DOH! Yes thats it, sorry for the silly question it all works now.

Thanks very much for the help.

Kind regards,

ARC