Does anyone have a good guide to designing and error tracking/control system for C?

c, embedded

Solution

In my experience the strategies here fall into a few camps.

Use of global variables ala errno. How this works is essentially any function can store an error code in the global variable, so after executing the function you can read the error code to see if it executed properly. There are some obvious issues here when working in a multithreaded environment. Although it appears that POSIX.1c specifies a solution to that problem.

Have every function return an error code. For example:

RESULT_CODE my_function(int param1, int param2);

RESULT_CODE error_code = my_function(10, 2);

The problem with this approach is that you lose your ability to return values from the function directly.

Every function has an extra parameter that stores the result code. For example:

void my_function(int param1, int param2, RESULT_CODE *err);

RESULT_CODE error_code;
my_function(10, 2, &error_code);
switch (error_code)
{
    case RESULT_OK:
        // all OK
        break;
    case RESULT_NO_MEM:
        // out of memory
        break;
    // etc...
}

I've seen this approach used successfully in commercial RTOS, and personally prefer it since I find it the least restrictive. The only potential disadvantage is that you have to explicitly declare a variable to store the error code, even if you don't care about the result. In some sense I actually kind of like that requirement, though, since it forces you to be constantly thinking about how errors are going to be handled.

Problem

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