os ipc · high

Process Memory Layout

Where every variable lives - stack, heap, .bss, .data, .text - and how the stack and heap grow toward each other.

The code

int g = 42;             // initialized global   -> .data
static int s;           // uninitialized static -> .bss
const char* msg = "hi"; // "hi" -> .text ; msg -> stack
int main() {
    int x = 1;           // local -> stack
    int* p = new int(7); // p -> stack ; *p -> heap
}

What this lesson walks through

1. 01A process's virtual address space
2. 02Code & literals live in .text (read-only)
3. 03Initialized globals -> .data
4. 04Uninitialized statics -> .bss
5. 05String literal -> .text ; pointer -> stack
6. 06Locals live on the stack (grows down)
7. 07new allocates on the heap (grows up)
8. 08The whole map

Every process gets a virtual address space split into regions. High addresses sit at the top, low at the bottom. Knowing what lives where explains lifetimes, sizeof, and crashes.