How to type cast an void pointer to array pointer in c?-CodePudding

**The dynamically allocated functions malloc,calloc,realloc in the stdlib library returns the void pointer

I want to convert the void pointer retuned to an array pointer is it possible to do so **

void* x=malloc(6*sizeof(int));
int (*ptr)[3];

Can we typecast x and assign it to ptr ?

CodePudding user response：

You can implicitly convert x to ptr via the assignment:

int (*ptr)[3] = x;

or use an explicit cast:

int (*ptr)[3] = (int (*)[3]) x;

As x is a pointer to array of 6 ints, I am not sure why you want a pointer to the first 3 of these. gcc -Wall -Wextra ... doesn't even generate a warning for out of bound access printf("%d\n", (*ptr)[4]); so why use a a plain int *ptr?

CodePudding user response：

The 'normal' way to do this is

int *ptr = malloc(6*sizeof(int));

or maybe

int *ptr = malloc(3*sizeof(int));

since you dont seem to know if you want 3 or 6 ints