Is it on the Stack or Heap?
I have some C code that is something of a puzzle. For a reason to do with this code, I'm wondering how I can tell if a struct object is ending up on the heap or stack?
The objects are not being created with malloc or calloc . They start their life in the form of an array. For the purposes of this post, I'm going to call the struct Emp.
Emp myEmp[6];
/* Each myEmp[?] item is populated in code */
The objects are sorted and manipulated in various ways and at some point, the objects are copied and then handed to a array-pointer. The copy is done via memcpy . The objects are then put in to something like: Emp* emps_a[6] .
The objects go from a copy and are assigned in to the above emps_a.
int i;
for( i = 0; i < n; i++ )
{
emps_a[i] = myEmpsCopy + i;
}
I'm not sure if some or any of this has bearing on my question. I never need free() or do memory clean up... I'm afraid I don't know too much about C.
The help is greatly appreciated.
Leaving global variables and variables declared with static modifier (which are allocated in a separate memory region) aside, local variables declared in a function body are allocated on the stack whereas whatever you call malloc for is allocated on the heap. Also, C99 variable sized arrays and memory allocated with _alloca will end up on stack.
int* x[10]; // The addresses are held on the stack
int i; // On the stack
for(i = 0; i < 10; ++i)
x[i] = malloc(sizeof(int)*10); // Allocates memory on the heap
For example, in the above code, there's an array of int* values on the stack holding addresses to 10 different locations in the heap.
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