Writing to a shared memory segment causes segmentation fault.

Issue

• Writing to a shared memory segment causes segmentation fault.

  1 #include <stdio.h>
  2 #include <sys/types.h>
  3 #include <sys/ipc.h>
  4 #include <sys/msg.h>
  5 #include <sys/mman.h>
  6 #include <sys/stat.h>
  7 #include <fcntl.h>
  8 #include <string.h>
  9 #include <stddef.h>
 10 #include <errno.h> 
 11 
 12 #define PROBEFTOK1 "/var/www/html/specialemptyftokfile.php"  
 13 #define PROBEFTOK2 53  
 14 
 15 int main() {
 16         key_t key;
 17         int msqid;
 18         void *shmptr;
 19         int i;  
 20         
 21         key = ftok(PROBEFTOK1,PROBEFTOK2);
 22         msqid = shmget(key,200,(IPC_CREAT | 438));
 23         printf("msqid %d\n",msqid);  
 24         shmptr = shmat(msqid,NULL,0);
 25         printf("shmptr: %p\n",shmptr);
 26         strcpy(shmptr,"1234");  
 27 }