shm_map.c

#include <stdio.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include "map_definitions.h"

int main ()
{
        int segment_id;
        char* shared_memory;
        const int shared_segment_size = sizeof(char) * MAP_WIDTH * MAP_HEIGHT;
        int i, j;

        /* Allocate a shared memory segment.  */
        segment_id = shmget (SHM_MAP_KEY , shared_segment_size,
                             IPC_CREAT | IPC_EXCL | S_IRUSR | S_IWUSR);

        /* Attach the shared memory segment.  */
        shared_memory = (char*) shmat (segment_id, 0, 0);

        /* Initialize Map Memory */
        for (j=0;j<MAP_HEIGHT;j++){
                for(i=0;i<MAP_WIDTH;i++){
                        *(shared_memory+i+j*MAP_WIDTH)=' ';
                }
        }
        printf("Map memory initialized\n");
        
        /* Main boucle */
        do {
                printf("Enter a modification on the map (-1 to exit)\n");
                printf("x="); scanf("%d",&i);
                printf("y="); scanf("%d",&j);
                if ((i<MAP_WIDTH) && (j<MAP_HEIGHT) && (i>=0) && (j>=0)) *(shared_memory+i+j*MAP_WIDTH)='#';
        } while((i!=-1) && (j!= -1));
        
        /* Deatch the shared memory segment.  */
        shmdt (shared_memory);

        /* Deallocate the shared memory segment.  */
        shmctl (segment_id, IPC_RMID, 0);

        return 0;
}

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