如何在整数指针数组的C中检查NULL？

Question

I have a fixed size array of integer pointers where I want to allocate from heap only if it is needed, but I can't seem to be able to get the following NULL check to work. malloc never get called first.

int* seqList[n];
for (int i = 0; i < q; i++) {
    int type, x, y;
    scanf("%d", &type);
    scanf("%d", &x);
    scanf("%d", &y);
    if (type == 1) {
        if (seqList[x] != NULL) {
            int size = sizeof(seqList[x])/sizeof(int*);
            seqList[x] = realloc(seqList[x], (size + 1)*sizeof(int*));
            seqList[x][size] = y;
        }
        else {
            seqList[x] = malloc(sizeof(int*));
        }
    }
    else{
        ...
    }
}

Answer 1

Thanks, BLUEPIXY and AnT. It seems that there isn't any other solution, but to initialize the array as mentioned here

for (i = 0; i < n; i++)
    seqList[i] = NULL;

Answer 2

You have to initialize it to 'NULL' to NULL check the array of pointers .

  int* seqList[n] = {NULL};

or

for ( i =0 ; i < n ; i++)
seqList[i] = NULL;