C & PHP: Storing settings in an integer using bitwise operators?

Question

I\'m not familiar with bitwise operators, but I have seem them used to store simple settings before.

I need to pass several on/off options to a function, and I\'d li

Answer 1

It works pretty much the same way in both languages, a side by side comparison:

C:

#include 
#include 

#define FLAG_ONE 0x0001
#define FLAG_TWO 0x0002
#define FLAG_THREE 0x0004
#define FLAG_FOUR 0x0008
#define FLAG_ALL (FLAG_ONE|FLAG_TWO|FLAG_THREE|FLAG_FOUR)

void make_waffles(void)
{
   printf("Yummy! We Love Waffles!!!\n");
}

void do_something(uint32_t flags)
{
    if (flags & FLAG_TWO)
         make_waffles();
}

int main(void)
{
    uint32_t flags;

    flags |= FLAG_ALL;

    /* Lets make some waffles! */
    do_something(flags);

    return 0;
}

PHP:

Note, you don't absolutely need to use constants, I just use them out of habit. Both examples will run, I compiled the C version via gcc -Wall flags.c -o flags. Change flags in either example to anything but FLAG_TWO or FLAG_ALL and (sadly) no waffles will be made.

In the C version, you don't have to tickle the preprocessor, it could quite easily be an enum, etc - that's an exercise for the reader.