43 lines
659 B
C
43 lines
659 B
C
#include <sys/types.h>
|
|
#include <sys/mman.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <fcntl.h>
|
|
#include "check.h"
|
|
|
|
int main()
|
|
{
|
|
int fd;
|
|
char *x;
|
|
FILE *fp;
|
|
char buf[40];
|
|
|
|
fd = open("my.file", O_CREAT | O_TRUNC | O_RDWR, 0644);
|
|
|
|
CHECK (fd != -1);
|
|
|
|
CHECK (write (fd, "abcdefgh", 8) == 8);
|
|
|
|
x = (char *)mmap (0, 20, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
|
|
|
|
CHECK (x != MAP_FAILED);
|
|
|
|
x[3] = 'j';
|
|
|
|
CHECK (munmap (x, 20) == 0);
|
|
|
|
CHECK (close(fd) != -1);
|
|
|
|
fp = fopen("my.file","r");
|
|
|
|
CHECK (fp != NULL);
|
|
|
|
CHECK (fread(buf, 1, 20, fp) == 8);
|
|
|
|
CHECK (strncmp (buf, "abcjefgh", 8) == 0);
|
|
|
|
exit (0);
|
|
}
|
|
|