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#include <assert.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <unistd.h>
static void test_anonymous(void)
{
int pagesize = getpagesize();
char *page;
int ret;
page = mmap(NULL, pagesize, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
assert(page != MAP_FAILED);
/* Check that mprotect() does not interfere with MADV_DONTNEED. */
ret = mprotect(page, pagesize, PROT_READ | PROT_WRITE);
assert(ret == 0);
/* Check that MADV_DONTNEED clears the page. */
*page = 42;
ret = madvise(page, pagesize, MADV_DONTNEED);
assert(ret == 0);
assert(*page == 0);
ret = munmap(page, pagesize);
assert(ret == 0);
}
static void test_file(void)
{
char tempname[] = "/tmp/.cmadviseXXXXXX";
int pagesize = getpagesize();
ssize_t written;
char c = 42;
char *page;
int ret;
int fd;
fd = mkstemp(tempname);
assert(fd != -1);
ret = unlink(tempname);
assert(ret == 0);
written = write(fd, &c, sizeof(c));
assert(written == sizeof(c));
page = mmap(NULL, pagesize, PROT_READ, MAP_PRIVATE, fd, 0);
assert(page != MAP_FAILED);
/* Check that mprotect() does not interfere with MADV_DONTNEED. */
ret = mprotect(page, pagesize, PROT_READ | PROT_WRITE);
assert(ret == 0);
/* Check that MADV_DONTNEED resets the page. */
*page = 0;
ret = madvise(page, pagesize, MADV_DONTNEED);
assert(ret == 0);
assert(*page == c);
ret = munmap(page, pagesize);
assert(ret == 0);
ret = close(fd);
assert(ret == 0);
}
int main(void)
{
test_anonymous();
test_file();
return EXIT_SUCCESS;
}
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