Hands-On System Programming with C++

The basics for writing a program

When writing a program, including system programming, there are a few different types of memory that can be leveraged by the author:

• Global memory
• Stack memory
• Heap memory

Global memory exists in the program itself, is allocated by the OS's loader, and generally exists in two different locations (assuming ELF binaries):

• .bss: zero-initialized (or uninitialized) memory
• .data: value-initialized memory

Consider the following example:

#include <iostream>int bss_mem = 0;int data_mem = 42;int main(){    std::cout << bss_mem << '\n';    std::cout << data_mem << '\n';}// > g++ -std=c++17 scratchpad.cpp; ./a.out// 0// 42

Although used a lot in system programming, global memory is usually discouraged in favor of stack ...