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Sraman
Associate II
April 3, 2024
Solved

Adding new c source files to my project and navigating through them

Hi all, I am fairly new in using STM32CubeIDE. I am working with three peripherals (uart1, uart2 and CAN) as also a timer interrupt in the STM32F103C8. I have written all the code in the main.c file. It is working but the coding is a bit jumbled up. For better readability, I want to put different functions of the three peripherals and the timer in different source files and call them from the main function. I am adding new c source files in the src folder but I have trouble in accessing the functions placed in these files from the main.c file. Can anybody please guide me in this matter?

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Andrew Neil
Andrew NeilBest answer
Super User
April 3, 2024

As @mƎALLEm said, you use header files (.h) to provide the declarations of the things you want to share.

This is standard C stuff - nothing specific or special to CubeIDE:

https://c-faq.com/decl/decldef.html 

 

eg, file.h provides declarations:

extern int variable1;

extern char variable1;

extern float variable1;

void function_1( void );

 

file.c provides definitions (or "implementations"):

int variable1;

char variable2;

float variable3;

void function_1( void )
{
 // your code here
}

 

Now, for example, your main.c can access things from file.c by #including file.h:

#include "file.h"

int main( void )
{
 int local_variable1 = 2 * variable1; // use the variables from file.c
 char local_variable2 = 3 + variable2;
 float local_variable3 = 2.3 / variable1;

 function_1(); // call the function from file.c
 :
 :

 

Update: https://community.st.com/t5/stm32cubeide-mcus/adding-new-c-source-files-to-my-project-and-navigating-through/m-p/658310/highlight/true#M25925 

 

Here is a pictorial summary:

AndrewNeil_0-1722589349504.png

 

PS:

More on declarations vs definitions (including the difference between preprocessor definitions, and function/variable definitions):

https://community.st.com/t5/stm32-mcus-embedded-software/use-of-c-or-h-files/m-p/793732/highlight/true#M62344

#DeclDef 

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
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9 replies

mƎALLEm
mƎALLEm
ST Technical Moderator
April 3, 2024

You need to export these functions in .h files.

Then include these .h files in your main.c.

To give better visibility on the answered topics, please click "Best answer" on the reply which solved your issue or answered your question.
    SramanAuthor
    Associate II
    April 3, 2024

    Dear SofLit,

    Can you please share some example codes or some reading material?

    mƎALLEm
    mƎALLEm
    ST Technical Moderator
    April 3, 2024

    One of the examples you can refer to is BSP example in the STM32CubeF1 from here.

    If you look at the main.h file already included in main.c, there are many .h files related to the BSP source code:

    #include "stm32f1xx_hal.h"
#include "stm3210e_eval.h"
#include "stm3210e_eval_lcd.h"
#include "stm3210e_eval_sd.h"
#include "stm3210e_eval_audio.h"
#include "stm3210e_eval_nor.h"
#include "stm3210e_eval_sram.h"
#include "stm3210e_eval_nand.h"
#include "stm3210e_eval_serialflash.h"
#include "stm3210e_eval_tsensor.h"

    The source files are located here.

    So the APIs defined in .c files are exported in .h files which in turn included in main.h which finally included in main.c. So all the functions defined in these drives will be seen in main.c file.

    Don't forget to add the include path(s) in your IDE.

     

    To give better visibility on the answered topics, please click "Best answer" on the reply which solved your issue or answered your question.
      Rim LANDOLSI
      Rim LANDOLSI
      ST Employee
      April 3, 2024
      Hello @Sraman   and welcome to the community,
       
      To link functions in main.c to separate C files, you can follow this example steps:
      • Add the source file (somm.c) to the src folder:

       

      int sommm(int a, int b){

	return(a+b);
}

       

      • Add header file (somm.h) under Inc folder:
      #ifndef INC_SOM_H_
#define INC_SOM_H_

int sommm(int,int);

#endif /* INC_SOM_H_ */
      •  In main.c, include the header file:
       #include "som.h"
       
      Then use the function you want
       
       
      Hope this helps!
       
      Thanks,
      Rim.
        SramanAuthor
        Associate II
        April 5, 2024

        Thanks everybody. As @Andrew Neil said, it is standard C stuff and I managed to do the coding.

          Andrew Neil
          Andrew Neil
          Super User
          April 5, 2024

          You're welcome.

          One thing I omitted to mention is that it's good to also #include your file.h header in your file.c source file.

          So, in file.c:

          #include "file.h" // contains the declarations

 // here are the definitions:
int variable1;

char variable2;

float variable3;

void function_1( void )
{
 // your code here
}

           

          This means that the Compiler, when it compiles file.c, gets to see both the declaration in file.h and the definitions in file.c - and, thus, can warn you if there's any discrepancy.

          A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
          SramanAuthor
          Associate II
          April 5, 2024

          Yeah, I am already doing this.

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