Clever Geek Handbook

Calling a main function from another function in C

I have a main function that performs several functions during initialization and then starts a while loop waiting for commands from the UART.

When I see a certain command (say reset), I call a function that returns a value. I want to do the following:

  • Save return value
  • Run the main function again with the returned value. The return value is required during the initialization of the main functions.

I'm new to C and I can't seem to find a way to store the value of a variable in the main.

+3


source to share


3 answers


As I understand it, you essentially have the following setup:

int main(int argc, char *argv[]) {
    int value = something_from_last_reset;
    perform_initialization(value);
    while(1) {
        int next_command = wait_for_command();
        if(next_command == RESET_COMMAND) {
            value = get_value();
            // somehow restart main() with this new value
        }
    }
    return 0;
}

Here you can choose one of the following methods:



// global
int value = some_initial_value;

void event_loop() {
    while(1) {
        int next_command = wait_for_command();
        if(next_command == RESET_COMMAND) {
            value = get_value();
            return; // break out of the function call
        }
    }
}

int main(int argc, char *argv[]) {
    while(1) {
        perform_initialization(value);
        event_loop();
    }
    return 0;
}

This essentially allows you to "escape" the event loop and initialize over and over again.

+5


source


just wrap yours main

in an endless loop.



int main(void)
{
    int init_val = 0;
    while (1)
    {
        // your code ...
        init_val = some_function();
    }
}
+2


source


In theory this is possible, but it's kind of like the paradigms of discontinuities and re-calling a function without letting it finish and return will quickly fill your call stack unless you take steps to deploy it behind the compiler.

A more common solution would be to write main () as one giant infinite loop {1}. You can do all of your work in an innner office or whatever, and have it in such a way that if you get the new value you want, you can sink to the bottom and go back, effectively rerun main with the new state.

+2


source






More articles:


All Articles