Bitfields programming

C and C++ programming

Example

#include <stdio.h>

void main( void ) {
struct display {
    unsigned format : 1;   // 24 hour or 12 hour format
    unsigned pm     : 1;   // PM and AM leds. If 12 hour format pm or am (pm=0 is am)
    unsigned alarm  : 1;   // Alarm on/off LED.   
    unsigned digit1 : 4;   // Hour MSD 7 segment
    unsigned digit2 : 4;   // Hour LSD 7 segment
    unsigned digit3 : 4;   // Minute MSD 7 segment
    unsigned digit3 : 4;   // minute LSD 7 segment
};

Links

• IBM on C bitfields
• Using Bitfields Effectively (volatile example)