Error Handling 2: One Solution

Example Solution

Below is a basic and incomplete solution to the divide by zero problem presented in the previous section.

The solution works as follows: Use an if statement to catch the case that val2 (the denominator) is zero. In the case that val2 is zero, do nothing with the operands and report the error through an event.

Use an if statement in MathReceiver.cpp to catch when the denominator is zero:

// In: MathReceiver.cpp
F32 res = 0.0;
switch (op.e) {
        case MathOp::ADD:
            res = val1 + val2;
            break;
        case MathOp::SUB:
            res = val1 - val2;
            break;
        case MathOp::MUL:
            res = val1 * val2;
            break;
        case MathOp::DIV:
            if ( val2 == 0 ){

              break; 
            }
            res = val1 / val2;
            break;
        default:
            FW_ASSERT(0, op.e);
            break;
    }

Technically speaking, this solution will prevent the error, but it would be good to output some error message before throwing away the operands and returning the default res.

Create an event to notify that a divide by zero command was received by the MathReceiver:

# In: MathRecevier.fpp
@ Commanded to divide by zero 
event DIVIDE_BY_ZERO   \
    severity activity high \
    id 3 \
    format "ERROR: Received zero as denominator. Opperands dropped."

Write your own error message between the quotes after format!

Add your even into the case where MathOp::DIV and val2 is 0:

case MathOp::DIV:
    //step 2 
    if ( val2 == 0 ){
        this->log_ACTIVITY_HI_DIVIDE_BY_ZERO(); 
        break; 
    }

Summary

You just created a way to not only handle the case where MathReceiver is asked to divide by 0, you also created an event to report that an error has occurred. As a challenge, try to handle more of the cases and problems discussed in Error handling 1.

Congratulations!!!

You have finished the MathComponent Tutorial. You have now experienced a significant part of F’ and are ready to start building your own deployments.