64 lines
1.4 KiB
C
64 lines
1.4 KiB
C
|
/* This file is part of the sample code and exercises
|
||
|
|
* used by the class "Advanced Programming in the UNIX
|
||
|
|
* Environment" taught by Jan Schaumann
|
||
|
|
* <jschauma@netmeister.org> at Stevens Institute of
|
||
|
|
* Technology.
|
||
|
|
*
|
||
|
|
* This file is in the public domain.
|
||
|
|
*
|
||
|
|
* You don't have to, but if you feel like
|
||
|
|
* acknowledging where you got this code, you may
|
||
|
|
* reference me by name, email address, or point
|
||
|
|
* people to the course website:
|
||
|
|
* https://stevens.netmeister.org/631/
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <err.h>
|
||
|
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <unistd.h>
|
||
|
|
|
||
|
|
#define MALLOC_SIZE 1024 * 1024
|
||
|
|
|
||
|
|
void
|
||
|
|
printMalloc(void *p, int s) {
|
||
|
|
(void)printf("malloc/realloc %d\n", s);
|
||
|
|
(void)printf("begins at 0x%12lX\n", (unsigned long)p);
|
||
|
|
(void)printf("ends at 0x%12lX\n", (unsigned long)p+s);
|
||
|
|
(void)printf("\n");
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
main() {
|
||
|
|
void *ptr;
|
||
|
|
|
||
|
|
if ((ptr = malloc(BUFSIZ)) == NULL) {
|
||
|
|
err(EXIT_FAILURE, "malloc");
|
||
|
|
/* NOTREACHED */
|
||
|
|
}
|
||
|
|
printMalloc(ptr, BUFSIZ);
|
||
|
|
|
||
|
|
/* shrink */
|
||
|
|
if ((ptr = realloc(ptr, BUFSIZ / 2)) == NULL) {
|
||
|
|
err(EXIT_FAILURE, "realloc");
|
||
|
|
/* NOTREACHED */
|
||
|
|
}
|
||
|
|
printMalloc(ptr, BUFSIZ / 2);
|
||
|
|
|
||
|
|
/* grow */
|
||
|
|
if ((ptr = realloc(ptr, MALLOC_SIZE)) == NULL) {
|
||
|
|
err(EXIT_FAILURE, "realloc");
|
||
|
|
/* NOTREACHED */
|
||
|
|
}
|
||
|
|
printMalloc(ptr, MALLOC_SIZE);
|
||
|
|
|
||
|
|
/* shrink, but larger than initial allocation */
|
||
|
|
if ((ptr = realloc(ptr, BUFSIZ * 2)) == NULL) {
|
||
|
|
err(EXIT_FAILURE, "realloc");
|
||
|
|
/* NOTREACHED */
|
||
|
|
}
|
||
|
|
printMalloc(ptr, BUFSIZ * 4);
|
||
|
|
|
||
|
|
return EXIT_SUCCESS;
|
||
|
|
}
|