Allocation to Pointers - c

Question

I work with char ****pCourses
int Courses(char ****pCourses, int ****pGrades, int **pCount, int *count)
{
char *buffer=NULL;
char letter;
int j=0, i;
int size=20;
int countCourse=0, sumCourses=0;
buffer=(char *)malloc(size*sizeof(char));
do
{
scanf("%c",&letter);
}while(letter==32);
while(letter!=10)
{
while(letter!=',')
{
//in case we need to expend the buffer
if(j>size)
{
size*=2;
buffer=(char *)realloc(buffer,size*sizeof(char));
}
buffer[j]=letter;
j++;
//The new letter from the name of course
scanf("%c",&letter);
}
//The end of the name of course
buffer[j]='\0';
j=0;
if(countCourse==0)
{
*pCount=(int *)realloc(*pCount, ((*count)+1)*sizeof(int));
(*pCount)[*count]=1;
}
else
(*pCount)[*count]++;
//Add the course's name to the system
*pCourses=(char ***)realloc(*pCourses, ((*count)+1)*sizeof(char ***));
(*pCourses)[*count]=(char **)realloc((*pCourses)[*count],(countCourse+1)*sizeof(char *));
((*pCourses)[*count])[countCourse]=(char *)malloc(strlen(buffer)+1);
strcpy(((*pCourses)[*count])[countCourse], buffer);
countCourse++;
scanf("%c",&letter);
}
free(buffer);
return 0;
}
while running I get a problem because of the next line:
(*pCourses)[*count]=(char **)realloc((*pCourses)[*count],(countCourse+1)*sizeof(char *));
that leads me to this part (from dbgheap.c):
{
while (nSize--)
{
if (*pb++ != bCheck)
{
return FALSE;
}
}
return TRUE;
}
does someone know what it means or why does this happen?

Answer 1

I think you've already been told what the problem is. All the alloc-type functions can fail and you should test for that and ideally write code that is robust enough to code with a failure.
Note that repeatedly using realloc() is not a good idea. If you expect to have to repeatedly add ( or remove ) data then you should be using a different structure, like a linked list or tree, which are designed to allow adding and removing data on the fly.