GoKawiilvoid * p = malloc ( 13 );
Almost all of us has seen this before when writing a safe c program. we know what this line does, atleast we know the purpose of it,
ask for 13 bytes, get 13 bytes
that’s what i thought when i started building this on a friday out of curiosity. 30 mins into it, without writing a single line of code… i knew that this almost never happens.
this simple line holds multiple interesting computations and allocations in itself under-the-hood.
for example, when I request 13 bytes.
actually reserved:
+--------+--------------+---------+-------------+ | Header | Back Pointer | Padding | User Memory | +--------+--------------+---------+-------------+
the user memory is the only thing we are gonna use and the *p returns the start of that memory. all the others are just there… not for usage.. why is that??
i wondered the same, instead of going into theory.. let’s build a allocator and free.
... continue reading