Everything is just bytes in memory

One of the reasons I keep coming back to C is that it doesn’t lie to you. A C program is, at the end of the day, nothing but bytes in memory. There is no abstraction beyond that you have to take on faith.

Consider a struct:

struct point {
    int   x;   // 4 bytes
    int   y;   // 4 bytes
    char  tag;  // 1 byte
};              // sizeof == 12, not 9

The sizeof is 12, not 9: the compiler pads tag so the next point in an array stays aligned. Nothing magical happened; the rules are knowable, and you can predict the layout exactly. That predictability is the whole appeal.

You can walk the raw bytes yourself:

struct point p = { .x = 1, .y = 2, .tag = 'a' };
unsigned char *raw = (unsigned char *)&p;
for (size_t i = 0; i < sizeof p; i++)
    printf("%02x ", raw[i]);

Higher-level languages give you objects, garbage collection, hidden allocations. Useful, often. But C, and the assembly it compiles to, hands you the naked, sometimes bitter, truth: you know exactly what the machine is going to do, and nothing is hidden.

That’s the stuff I find worth writing about.