osi

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ipc.h>
#include <sys/shm.h>

#define MAX_LEN   10000
#define SELF_FILE "06-1-write.c"

int main(int argc, char *argv[]) {
    char c;
    FILE *self;
    int i = 0;

    char *array;
    int shmid;
    int new = 1;
    char pathname[] = SELF_FILE;
    key_t key;

    if ((key = ftok(SELF_FILE, 0)) < 0) {
        printf("Can\'t generate key");
        exit(-1);
    }

    if ((shmid = shmget(key, MAX_LEN * sizeof(char), 0666 | IPC_CREAT | IPC_EXCL)) < 0) {
        if (errno != EEXIST) {
            printf("Can\'t create shared memory\n");
            exit(-1);
        } else {
            if ((shmid = shmget(key, MAX_LEN * sizeof(char), 0)) < 0) {
                printf("Can\'t find shared memory\n");
                exit(-1);
            }
            new = 0;
        }
    }

    if ((array = (char *)shmat(shmid, NULL, 0)) == (char *)(-1)) {
        printf("Can't attach shared memory\n");
        exit(-1);
    }

    self = fopen(SELF_FILE, "r");
    if (!self) {
        printf("Can't read file");
        exit(-1);
    }

    while ((c = getc(self)) != EOF) {
        array[i++] = c;
    }
    fclose(self);

    if (shmdt(array) < 0) {
        printf("Can't detach shared memory\n");
        exit(-1);
    }

    return 0;
}





#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ipc.h>
#include <sys/shm.h>

#define MAX_LEN   10000
#define SELF_FILE "06-1-write.c"

int main(int argc, char *argv[]) {
    char c;
    int i;

    char *array;
    int shmid;
    int new = 1;
    char pathname[] = SELF_FILE;
    key_t key;

    if ((key = ftok(SELF_FILE, 0)) < 0) {
        printf("Can't generate key");
        exit(-1);
    }

    if ((shmid = shmget(key, MAX_LEN * sizeof(char), 0666 | IPC_CREAT | IPC_EXCL)) < 0) {
        if (errno != EEXIST) {
            printf("Can't create shared memory\n");
            exit(-1);
        } else {
            if ((shmid = shmget(key, MAX_LEN * sizeof(char), 0)) < 0) {
                printf("Can't find shared memory\n");
                exit(-1);
            }
            new = 0;
        }
    }

    if ((array = (char *)shmat(shmid, NULL, 0)) == (char *)(-1)) {
        printf("Can't attach shared memory\n");
        exit(-1);
    }

    for (i = 0; i < MAX_LEN; ++i) {
        putchar(array[i]);
    }

    if (shmdt(array) < 0) {
        printf("Can't detach shared memory\n");
        exit(-1);
    }

    shmctl(shmid, IPC_RMID, NULL);

    return 0;
}