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#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);
}
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