1. #include <sys/mman.h>
2. #include <stdio.h>
3. #include <unistd.h>
4. #include <fcntl.h>
5. #include <string.h>
6. #include <stdlib.h>
7. #include <sys/types.h>
8.  
9. int main(int argc, char *argv[])
10. {
11.   char *addr;
12.   char *mfile = "lena.jpg";
13.   char infile[64];
14.   int fd01, fd02;
15.   pid_t pid;
16.  
17.   struct stat st;
18.  
19.   fd01 = open(mfile, O_RDWR);
20.  
21.   stat(mfile, &st);
22.  
23.   addr = (char*)mmap(NULL, st.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd01, 0);
24.  
25.   pid = fork();
26.  
27.   if(pid == 0)
28.   {
29.     execlp("display", "display","-update","2", mfile, 0 );
30.         //execlp("display", "display", "-update", "2", "MAP.jpg", NULL);
31.   }
32.   else
33.   {
34.     while(1)
35.     {
36.       gets(infile);
37.       fd02 = open(mfile, O_RDONLY);
38.       stat(fd02, &st);
39.       ftruncate(fd02, st.st_size);
40.       addr = (char*)mmap(addr, st.st_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd02, 0);
41.       read(fd02, addr, st.st_size);
42.       msync(addr, st.st_size, 0);
43.       close(fd02);
44.     }
45.   }
46.  
47.   munmap(addr, st.st_size);
48.   close(fd01);
49.  
50.  
51.   return 0;
52. }
53.