Volatile

Needed For:

• Prevent optimization when reading from a memory mapped device registers
• Delay Loops
  

Usage :

volatile int xyz;

or

int volatile xyz;

Note :
volatile may cause inefficient code. e.g the following code

hwReg &= ~FUNCTION_MASK;
hwReg |= FUNCTION_BIT;

instead use the following code

hwReg = (hwReg & ~FUNCTION_MASK) | FUNCTION_BIT;