Question

So, in my program, I have a variable

uint32_t buffer[16];

However, there are some times where I need to treat this as

uint8_t char_buffer[64];

The most obvious solution is a union. However, out of intellectual curiosity, is there another way to tell the compiler that I want to treat the array as an array of some arbitrary type? Something along the lines of

((uint8_t *)buffer)[i]

?

Answer 1

The casting approach is perfect. It will make the compiler treat the array as an array of ints. In your particluar case, use

((uint32_t *)buffer)[index];

As @JerryCoffin points out, however, there’s a probem with alignment. If you statically allocate the array statically as a char [], it won’t necessarily be 4-byte aligned (which is needed for integers). If you surely want to avoid this problem, use malloc() as it guarantees an appropriate alginment.