This is a plea for some advice on coding style from any of the experts on
the list.  I have written some I2C drivers for use under Windows for a
project, and whilst they are perfectly functional I feel that my coding
style could definately be improved.  Now, a function should preferably have
one entry and one exit.  However my code looks something like the function
below.  Here I am calling several functions that return a boolean to
indicate success or failure, and I want to exit the calling function if a
failure is returned.


bool _stdcall X9241Write(unsigned char address, unsigned char instruction)
{
/*
Function:               X9241Write
Arguments:      address = slave address of device, instruction = instruction
byte to send to pot
Return:                 True if success, false if fail.
Description:    Generic write command for instructions that required no
additional data.
*/

        unsigned char fullAddr;

    fullAddr = (unsigned char)(X9241_ADDR | (address & 0x0F));

    if(!I2CStart())
        return false;

    // send slave address
    if(!I2CTransmit(fullAddr))
        return false;

    if(!I2CGetAck())
        return false;

        // send the MSB
    if(!I2CTransmit(instruction))
        return false;

    if(!I2CGetAck())
        return false;

    if(!I2CStop())
        return false;

    return true;
}

Now I could nest all the if() statements, but to my mind this would become
far more confusing than the above, especially with some of the longer
functions.  Or perhaps set a local variable and check it before calling each
sub function i.e.

bool success;

success = I2CStart();

if(success)
        success = I2CTransmit(fullAddr);
if(success)
        success = I2CGetAck();

etc, etc...

This would work and I could use one return at the end, but to my mind a
failure at the top of the function causes unnecessary overhead in in
checking the success variable multiple times to reach the end of the
function. I could use a goto and a label at the end of the function, but
that seems infinitely worse than multiple returns.

Any other suggestions?

Regards

Mike

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