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62 lines
1006 B
62 lines
1006 B
#include <sys/types.h>
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#include <sys/ipc.h>
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#include <sys/shm.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#define SHMSZ 1024
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main(int argc, char **argv)
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{
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char c, tmp;
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int shmid;
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key_t key;
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char *shm, *s;
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/*
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* Shared memory segment at 1234
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* "1234".
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*/
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key = 1234;
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/*
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* Create the segment and set permissions.
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*/
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if ((shmid = shmget(key, SHMSZ, IPC_CREAT | 0666)) < 0) {
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perror("shmget");
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return 1;
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}
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/*
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* Now we attach the segment to our data space.
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*/
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if ((shm = shmat(shmid, NULL, 0)) == (char *) -1) {
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perror("shmat");
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return 1;
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}
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/*
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* Zero out memory segment
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*/
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memset(shm,0,SHMSZ);
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s = shm;
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/*
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* Read user input from client code and tell
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* the user what was written.
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*/
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while (*shm != 'q'){
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sleep(1);
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if(tmp == *shm)
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continue;
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fprintf(stdout, "You pressed %c\n",*shm);
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tmp = *shm;
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}
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if(shmdt(shm) != 0)
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fprintf(stderr, "Could not close memory segment.\n");
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return 0;
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}
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