Dynamic memory allocation with / without function - c

Question

I tried creating function that dynamically allocates memory for 2 dimensional array and put some integer values into the array. Overall, the function worked as expected but there were some error. So I did the same thing within main() and got the right result. My code is like below:
#include <stdlib.h>
#include <stdio.h>
void test(int d1, int d2, int ***p){
int value;
*p = (int **)(malloc(sizeof(int)*d1));
for (int i = 0; i < d1; i++){
(*p)[i] = (int *)(malloc(sizeof(int)*d2));
for (int j = 0; j < d2; j++){
(*p)[i][j] = i * 10 + j;
}
}
printf("\n");
}
int main(void){
int d1, d2;
int ** ptr;
printf("length of 1st dimension?\n");
scanf("%d", &d1);
printf("length of 2nd dimension?\n");
scanf("%d", &d2);
test(d1, d2, &ptr);
for (int i=0; i<d1; i++){
for (int j=0; j<d2; j++){
printf("%d ", ptr[i][j]);
}
printf("\n");
}
free(ptr);
ptr = (int **)(malloc(sizeof(int)*d1));
for (int i=0; i< d1; i++){
ptr[i] = (int *)(malloc(sizeof(int)*d2));
for (int j=0; j<d2; j++){
ptr[i][j] = i *10 +j;
}
}
printf("\n######################\n\n");
for (int i=0;i<d1;i++){
for (int j=0; j<d2;j++){
printf("%d ", ptr[i][j]);
}
printf("\n");
}
free(ptr);
return 0;
}`
When I passed 5 as a length of 1st and 2nd dimension, I got the result like below:
length of 1st dimension?
5
length of 2nd dimension?
5
532699424 32725 2 3 4
10 11 12 13 14
20 21 22 23 24
30 31 32 33 34
40 41 42 43 44
######################
0 1 2 3 4
10 11 12 13 14
20 21 22 23 24
30 31 32 33 34
40 41 42 43 44
I think, except that I passed pointer to pointer to pointer as an argument to the function, I did the same thing. However some values in the first row are different. And I got different value for the first row whenever I executed the function.
Could someone please let me know what I did wrong?
Thank you in advance.

Answer 1

The lines
*p = (int **)(malloc(sizeof(int)*d1));
ptr = (int **)(malloc(sizeof(int)*d1));
are wrong. The elements is int*, but only room for int is allocated per element.
This may cause trouble if int* is larger than int (for example, when int* is 8 bytes and int is 4 bytes).
The lines should be
*p = malloc(sizeof(int*)*d1);
ptr = malloc(sizeof(int*)*d1);
or (with risk of making mistake reduced by avoiding writing type manually)
*p = malloc(sizeof(*p)*d1);
ptr = malloc(sizeof(*ptr)*d1);
See also: c - Do I cast the result of malloc? - Stack Overflow