brk

I'm trying to understand the sbrk() function. From what I know: sbrk(0) returns the current address of the break and doesn't increment it. sbrk(size) increments the address of the break by size bytes and returns the previous address of the break. So I created something to test it: #include <unistd.h> #include <stdio.h> int main(void) { printf("sbrk(0) = %p\n", sbrk(0)); // should return value x printf("sbrk(0) = %p\n", sbrk(0)); // should return value x printf("sbrk(5) = %p\n", sbrk(5)); // should return value x printf("sbrk(0) = %p\n", sbrk(0)); // should return value x + 5 } So I'm expecting

According to Linux programmers manual: brk() and sbrk() change the location of the program break, which defines the end of the process's data segment. What does the data segment mean over here? Is it just the data segment or data, BSS, and heap combined? According to wiki: Sometimes the data, BSS, and heap areas are collectively referred to as the "data segment". I see no reason for changing the size of just the data segment. If it is data, BSS and heap collectively then it makes sense as heap will get more space. Which brings me to my second question. In all the articles I read so far, author