STM32CubdeIDE printing messages to UART only when in DEBUG mode

[LPetr.1]

Hello. I would like to print certain messages to UART only in DEBUG mode. These prints will not be necessary in release mode.

I have tried the following:

#ifdef DEBUG
	 printf("hello from debug \n");
#endif

And then I have built the project for both release and debug but the message is printed in both cases. How can I only get message to print in debug mode and not in release mode?

[Andrew Neil]

First, Are you sure that you actually did a full rebuild, and that you actually loaded the correct binary?

Once that's confirmed, if the problem persists, then you need to investigate where the DEBUG symbol is getting defined in the two buillds.

Note that it's common to have something like:

#ifdef DEBUG
	 #define DEBBUG_PRINT(X) printf X 
#else
	 #define DEBBUG_PRINT(X)
#endif

which you then use as:

DEBUG_PRINT(("stuff"));

which clutters the source less.

See, for example, https://stackoverflow.com/questions/1644868/define-macro-for-debug-printing-in-c

But that relies upon your DEBUG symbol working first...

[LPetr.1]

Unfortunately I still cannot get this to work. This is probabaly because my Debug symbol is not working properly as you have suggested..

Is there any way to test this? Do I need to change something in my project settings to ensure the DEBUG symbol to work ( it should be set to 0 when I select release mode and should be 1 when I select debug mode).

I have implemented the code that you have suggested, then I have built my project using release mode:

 

And then I just clicked "run"

[Andrew Neil]

"Is there any way to test this?"

STM32CubeIDE should shade code that's disabled by a #if

So try something like

#ifdef DEBUG
	 printf("debug \n");
#else
	 printf("non-debug \n");
#endif

"it should be set to 0 when I select release mode and should be 1 when I select debug mode"

No: You're testing whether it is defined, or is not defined.

If you're defining it as zero, then it is defined!

In that case, you'd need

#if DEBUG == 1
	 printf("debug \n");
#else
	 printf("non-debug \n");
#endif

Or, perhaps

#if DEBUG == 1
	 printf("debug \n");
#elif DEBUG == 0
	 printf("non-debug \n");
#else 
#error "DEBUG must only be set to 0 or 1"
#endif

[LPetr.1]

I am not defining DEBUG myself. I want the program to automatically recognise whether it is debug or release mode and set this DEBUG flag for me accordingly

[Andrew Neil]

If your prints are still printing, then it must be getting defined somewhere!

Do you get the shading correctly?

What happens if you do a 'Go to definition' on DEBUG ?

[LPetr.1]

It wont let me go to definition. Clicking go to declaration doesnt go anywhere.

[LPetr.1]

Do I need to add DEBUG symbol here?:

[Andrew Neil]

That's showing the 'Release' configuration - so you want DEBUG to not be defined.

Which seems correct.

Note that there are separate settings for C, C++, and Assembler.

It's common to define NDEBUG as a complement to DEBUG - so you might add that here.

NDEBUG and DEBUG should be mutually exclusive - you could check with

#if defined( DEBUG ) && defined( NDEBUG )
#error "Both DEBUG & NDEBUG are defined"
#endif

[LPetr.1]

Now I am getting more and more confused. It is very strange that such a simple task is so complex to achieve

[Andrew Neil]

It should be simple - DEBUG should just be defined for the 'Debug' configuration in the Project settings.

But that fact that it's not working shows that something's gone wrong ...

If those prints are still appearing, DEBUG must be getting defined somewhere.

Or you're not loading the code you think you are.

have you checked that?

[LPetr.1]

I am definately loading the right code because each time I change printf message and I can see it update.

I cant find this property page

[LPetr.1]

I have also tried the following:

#define DEBUG 0
 
#ifdef DEBUG
	 #define DEBUG_PRINT(X) printf X
#else
	 #define DEBUG_PRINT(X)
#endif

I have manually set the DEBUG variable to 0 and so the debug printf should not work if I understand this correctly. However, it is still printing

I have an RTOS task which is printing "test" periodically

void StartDefaultTask(void const * argument)
{
 /* USER CODE BEGIN 5 */
 /* Infinite loop */
 for(;;)
 {
	 DEBUG_PRINT(("test\n"));
	 osDelay(1000);
 }
 /* USER CODE END 5 */
}

st

[Andrew Neil]

"I have manually set the DEBUG variable to 0 and so the debug printf should not work if I understand this correctly"

You misunderstand.

I explained this earlier:

#define DEBUG 0

that is a definition of DEBUG; you have defined it to be zero - so it is defined!

Therefore

#ifdef DEBUG

will be true - so all the prints will be enabled.

"'ifdef" means "if defined"

If you want to test the value that has been defined, you need:

#if DEBUG == 1
	 #define DEBUG_PRINT(X) printf X
#else
	 #define DEBUG_PRINT(X)
#endif

[LPetr.1]

Ok I understand now. I did the following:

For release I define debug 0

 

For debug I define debug 1

 

Then in my main.c:

#if(DEBUG==1)
	 #define DEBUG_PRINT(X) printf X
#else
	 #define DEBUG_PRINT(X)
#endif

Now the DEBUG_PRINT only works when I am in debug mode exactly how I want to!

Thank you very much for your help

[Andrew Neil]

Note that it is more conventional for DEBUG to be either defined or not, and to test it with #ifdef.

Anyhow, if the issue is now resolved, please mark the solution:

 

[Piranha]

Instead of ==1 one of these should be used:

#if DEBUG != 0
#if DEBUG

Anyway, #ifdef is, of course, the most appropriate here.