How to read from named streams?

Question

linux

Hello. In front of me is the back to read two named streams and write to the third (created by me) the sum of the numbers that will come.
For this I wrote the following.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/shm.h>
 
#define SHMSZ 1000
 
int main(int argc, char *argv[]) {
 
    int num1, num2;
    num1 = atoi(argv[1]);
    num2 = atoi(argv[2]);
    int shmid,shmid1,shmid2;
    key_t key;
    int *shm1, *shm2, *shm3, *temp;
    key = 54321;
    printf("%d\n", key);
 
 
    if ((shmid = shmget(key, SHMSZ, IPC_CREAT | 0660)) < 0) {
       
        return 1;
    }
 
 
    if ((shm1 = (int *)shmat(shmid, NULL, 0)) == (int *) -1) {
 
        return 1;
    }
 
    if ((shm2 =  (int *)shmat(num1, NULL, 0)) == (int *) -1) {
 
        return 1;
    }
 
    if ((shm3 = (int *)shmat(num2, NULL, 0)) == (int *) -1) {
 
        return 1;
    }
 
    int count = 0;
    while (count < 100) {
        temp[count] = shm2[count] + shm3[count];
        count++;
    }
    memcpy(shm1, temp, (sizeof(temp)*10) );
    if(shmdt(shm1) < 0){ 
                return 1;
    }
    printf("%d\n",key);
    return 0;
}

However, the program does not produce the desired result (it turns out to add the numbers at a time). Where can I go wrong?