52 lines
1.4 KiB
C
52 lines
1.4 KiB
C
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/***********************************************************************************
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Code Inherited from Anon
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Massively Modified by Prawar Poudel, 3 Feb 2020 (pp0030@uah.edu)
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************************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#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 "header.h"
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main(int argc, char *argv[])
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{
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int id ;
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struct info *ctrl;
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if (argc < 3)
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{
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//error…;
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exit(3);
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}
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// get the id of the already created shared memory segment
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// .. function to create is same as getting id of the already created shared memory segment
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// .. notice the difference between the flags used in Process C and Process D
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if ( (id = shmget( key,MSIZ, 0 )) < 0 )
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{
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//error … ;
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exit(1) ;
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}
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// attach a local pointer to the shared memory
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ctrl = (struct info *) shmat( id, 0, 0);
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if ( ctrl <= (struct info *) (0) )
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{
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//error … ;
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exit(1) ;
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}
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// wait until Process C is ready to receive from process D
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while(ctrl->flag==0);
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/* copy command line data to shared memory */
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ctrl->c = argv[1][0] ;
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ctrl->length = atoi(argv[2]);
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ctrl->flag = 1;
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//detach the pointer from the shared memory
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// .. we do not need to delete here, can be done in either of the process
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shmdt(ctrl);
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exit(0);
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}
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