Hands-On System Programming with Linux

The exec Unix axiom

We learned in Chapter 2, Virtual Memory, which covered virtual memory, that a process can be visualized as a box (a rectangle), having a virtual address space (VAS); the VAS consists of homogeneous regions (technically, mappings) called segments. Essentially, a process's VAS is thus made up of several segments—text (code), data segments, library (and other) mappings, and a stack. For your convenience, the diagram representing a process's VAS is reproduced here:

Fig 1 : The process virtual address space (VAS)

The lower end has a virtual address of 0, and addresses increase as we go up; we have an upward-growing heap and ...