GNU Info

(libc.info)Allocating Cleared Space

---

Next: Efficiency and Malloc Prev: Changing Block Size Up: Unconstrained Allocation

---

Enter node , (file) or (file)node

Allocating Cleared Space
........................

   The function `calloc' allocates memory and clears it to zero.  It is
declared in `stdlib.h'.

 - Function: void * calloc (size_t COUNT, size_t ELTSIZE)
     This function allocates a block long enough to contain a vector of
     COUNT elements, each of size ELTSIZE.  Its contents are cleared to
     zero before `calloc' returns.

   You could define `calloc' as follows:

     void *
     calloc (size_t count, size_t eltsize)
     {
       size_t size = count * eltsize;
       void *value = malloc (size);
       if (value != 0)
         memset (value, 0, size);
       return value;
     }

   But in general, it is not guaranteed that `calloc' calls `malloc'
internally.  Therefore, if an application provides its own
`malloc'/`realloc'/`free' outside the C library, it should always
define `calloc', too.