C changing a pointer in a function - c

Question

I want to write a function that processes a string that looks like this:
|1,2,3,4|(1->2),(2->3),(3->1)|
The result should be a breaking down of the string into these strings:
1
2
3
4
(1->2)
(2->3)
(3->2)
This is my code:
int processPart(char*** dest, char* from) //Processes a half at a time
{
int len = 0;
char* cutout = strtok(from, ",");
while(cutout)
{
(*dest) = (char**)realloc(dest, (len + 1) * sizeof(char*)); <<<<<<<
(*dest)[len] = (char*)calloc(strlen(cutout) + 1, sizeof(char));
memcpy((*dest)[len], cutout, strlen(cutout));
cutout = strtok(NULL, ",");
len++;
}
return len;
}
void processInput(char*** vertices, char*** edges, char* input, int* sizev, int* sizee)
{
int vlen = 0, elen = 0;
char* string = input + 1;
char* raw_vertices;
char* raw_edges;
string[strlen(string)] = '\0';
raw_vertices = strtok(string, "|");
raw_edges = strtok(NULL, "|");
*sizev = processPart(vertices, raw_vertices); //First the vertices
*sizee = processPart(edges, raw_edges); //Then the edges
}
int main()
{
char* in = stInput(); //input function
char** c = NULL, **b = NULL;
int a, d, i;
processInput(&c, &b, in, &a, &d);
for(i = 0; i < a; i++)
{
printf("%s\n", c[i]);
}
printf("++++++++++++++++");
for(i = 0; i < d; i++)
{
printf("%s\n", b[i]);
}
return 0;
}
However, I get a corruption of the heap at the line marked by <<<<<<<
Anyone knows what my mistake is?

Answer 1

In the erroneous line
(*dest) = (char**)realloc(dest, (len + 1) * sizeof(char*));
a * is missing before the dest argument. You could have spotted this easier if you hadn't cluttered the expression with the useless cast. I'd write
*dest = realloc(*dest, (len + 1) * sizeof**dest);
- that way we can see better the matching of first argument and left operand of the assignment.