The malloc function is not supposed to initialize any value to any variable it is used on, like the malloc does. Why then do I keep getting the initialized value of every other varibale to be 0, after using the malloc function once in the program?

Here’s the code to reproduce the issue: –

#include <stdlib.h>
#include <stdio.h>

int main() {
  int* ptr = malloc(sizeof(int));

  int some_variable;
  printf("%dn", some_variable); // prints 0

  return 0;
}

Expected some garbage value to be printed but got 0. Even if malloc does allocate 0 to every unintialized memory block, how are variables like some_variable, completely out of the function’s scope getting affected?