Find if a register value has been written to by any external process

RegDirty( nDvc, nReg )

Returns 1 if the register has been written to by any other driver or system function. Returns 0 if not.

This function mostly has utility in the development of shared drivers.

It is used to track changes to a register, and simplifies handling of writeable registers.

Every register has a 'dirty' status flag. This flag is set if the register is written to by any function other than SetRegister inside the same driver. By executing this function, the dirty flag is reset to 0.

Returns 1 (dirty) or 0 (not dirty)

    if( RegDirty( nDvc, 5 ) ) {    // The register was touched
        // write value to external device
    } else {
        // read value from external device
        SetRegister( nDvc, 5, readvalue );
    }