The example is earlier in this thread. Here's the setup, and why I did it like that:
1) I have a main program loop in C++ in file application.cpp. That's what I want to run
2) I have a main.c generated by CubeMX. I don't want to rename main.c to main.cpp
3) I've determined that I will always call the application in my programs application.cpp, even though it may be a different project ( I have a program that writes main application loops for certain types of programs, just to mention it).
4) the main program (main.c) calls the bridge program before it goes into the loop. In main.c it looks like this:
/* USER CODE END Header_StartDefaultTask */
void StartDefaultTask(void const * argument)
{
/* USER CODE BEGIN 5 */
/* Infinite loop */
cpp_link();
// NEVER GETS HERE, cpp_link goes to application init and then loop
for(;;)
{
osDelay(10000);
}
/* USER CODE END 5 */
}
5) note that the main program loop does nothing, and I call my bridge program (C to C++) before the main loop. The main loop executes, but that's a "who cares" and it's going to spend most of its time in a delay. My bridge program is called cpp_link.
CPP_link.hpp looks like:
#ifndef CPP_LINK_HPP_
#define CPP_LINK_HPP_
#ifdef __cplusplus
extern "C"
{
#endif
void cpp_link (void);
#ifdef __cplusplus
}
#endif
#endif /* CPP_LINK_HPP_ */
since it's identical for all applications I write, it never needs to change, and the code in main.c can just be copied over.
CPP_LINK.cpp looks like this:
#include "CPP_LINK.hpp"
#include "APPLICATION.hpp"
#ifdef __cplusplus
extern "C"
{
#endif
void cpp_link (void)
{
APPLICATION_init();
}
#ifdef __cplusplus
}
#endif
CPP link never changes because the call to my program (application.cpp) never changes because the main executable routine is always called APPLICATION_init();
Since I'm using FreeRTOS, APPLICATION_init looks like this:
// ********************************************************************************************************************
// ******************************************************* APPLICATION INIT *******************************************
// ********************************************************************************************************************
void APPLICATION_init(void)
{
#ifdef _FREERTOS
xTaskCreate((TaskFunction_t) APPLICATION_TASK,
"APPLICATION",
24000,
NULL, 3,
&APPLICATION_task_handle);
#endif
}
Your settings for FreeRTOS will vary, of course.
The first few lines of the application itself look like this....
#ifdef _FREERTOS
void APPLICATION_TASK(void const * argument)
{
struct address_list_type A;
int display_number = 0; // incrementing display number
// ********************************************************************************************************************
// ******************************************************* APPLICATION VARIABLES **************************************
// ********************************************************************************************************************
struct SYSTEM_INSTALL_response install_response[40];
uint16_t which_install = 0;
int16_t i;
int x = 0, y = 0;
#ifdef _GRAPHICS
string main_caption;
#endif
// (more code follows.........)
So:
main.c (regenerated by CubeMX) calls cpp_link. Once the code is inserted in main.c, CubeMX doesn't change that code. CPP_link calls your application code.
That CPP_LINK calls the application_init code in my programs is just how I do things. CPP_link can call your C++ program loop directly. As you see, Application_init sets up my main program task (it then returns, and you get the very long main program loop with the delay of 10000). What you call from CPP_LINK is up to you, or even if it never comes back.
The reason for this design is that:
1) I don't have to change or rename main.c
2) I have a very small program (CPP_LINK) that does exactly what I need and was the experiment to see if it compiled
3) for me (and this may be unique), I have a program that builds application.cpp for me, depending on what project options I pick. So having fixed names (but variable content) makes sense, but that's only for what cpp_link calls.
All the other parts of my code are written to call C routines (if FreeRTOS) or if HAL layer routines. My main code is C++ which can just call C++. No C code calls C++ with the exception of the one call in main.c to cpp_link.
