volatile keyword

volatile.cpp

void main()
{
	// 'non_volatile_int == 1' will be optimized to be 'true' by compiler
	int non_volatile_int = 1;
	while( non_volatile_int == 1 /* true */ )
	{
		// code
	}
	
	// 'volatile_int == 1' won't be optimized by compiler
	volatile int volatile_int = 1;
	while( volatile_int == 1 )
	{
		// code
	}
}