void greet() { printf("Hello, world!\n"); } In this example, the greet function does not return any value; it simply prints a message to the console. alloc_page is not a standard function in most programming languages but refers to the concept of allocating a page of memory. In computer systems, memory is often managed in pages, which are fixed-size blocks of memory. The allocation of a page is fundamental in systems programming, especially when working with operating system APIs or in embedded systems.