/*
 * Sample program for brk system call  - No.45
 *
 * brk(2), sbrk(2) - change data segment size
 *
 * Synopsis
 *     #include <unistd.h>
 *
 *     int brk(void *end_data_segment);
 *     void *sbrk(ptrdiff_t increment);
 *
 * Description
 *     brk sets the end of the data segment to the value specified
 *     by end_data_segment, when the value is reasonable, the
 *     system does have enough memory and the process does not
 *     exceed its max data size (see setrlimit(2)).
 *
 *     sbrk increments the program's data space by increment
 *     bytes. sbrk isn't a system call, it is just a C library
 *     wrapper. Calling sbrk with an increment of 0 can be used
 *     to find the current location of the program break.
 *
 * Return value
 *     On success, brk returns zero, and sbrk returns a pointer
 *     to the start of the new area. On error, -1 is returned,
 *     and errno is set to ENOMEM.
 */

#include <stdio.h>

main()
{
	void *ptr;

	ptr = (void *)sbrk(0);
	printf("%0X\n", ptr);
	brk(ptr + 4);
	printf("%0X\n", sbrk(0));
}