I have a pointer to a struct and one of the objects in the struct is a int **. The double pointer is used to dynamically allocate memory for a 2d array. I am having trouble figuring out how to free the memory for this array. Any ideas?
struct time_data {
int *week;
int *sec;
int **date;
};
typedef struct time_data time_data;
time_data *getTime(time_data *timeptr, int rows, int cols) {
int i = 0;
time_data time;
// allocate memory for time.date field
time.date = (int **)malloc(rows*(sizeof(int *))); // allocate rows
if(time.date == NULL)
printf("Out of memory\n");
for(i=0; i<rows; i++) {
time.date[i] = (int *)malloc(cols*sizeof(int));
if(time.date[i] == NULL)
printf("Out of memory\n");
}
timeptr = &time;
return timeptr;
}
int main(int argc, const char * argv[]) {
time_data *time = NULL;
int rows = 43200, cols = 6;
int i;
time = getTime(time, rows, cols);
for(i=0; i<rows; i++)
free(time->date[i]); // problem here
free(time->date);
}
Modified Version (in case anyone else has similar issue)
struct time_data {
int *week;
int *sec;
int **date;
};
typedef struct time_data time_data;
time_data *getTime(int rows, int cols) {
int i = 0;
time_data *time = malloc(sizeof(*time));
// allocate memory for time.date field
time->date = (int **)malloc(rows*(sizeof(int *))); // allocate rows
if(time->date == NULL)
printf("Out of memory\n");
for(i=0; i<rows; i++) {
time->date[i] = (int *)malloc(cols*sizeof(int));
if(time->date[i] == NULL)
printf("Out of memory\n");
}
return time;
}
int main(int argc, const char * argv[]) {
time_data *time = NULL;
int rows = 43200, cols = 6;
int i;
time = getTime(rows, cols);
for(i=0; i<rows; i++)
free(time->date[i]); // problem here
free(time->date);
return 0;
}
printf("Out of memory\n");
is not enough, you shold abort and not dereferene the pointer. – Iharob Al AsimigetTime
is returning the address of a local variable, which is not valid. – Barmar