Allocates an area of zeroed memory. This function is AST-
    reentrant.

    Format

      #include  <stdlib.h>

      void *calloc  (size_t number, size_t size);

1  –  Function Variants

    The calloc function has variants named _calloc32 and _calloc64
    for use with 32-bit and 64-bit pointer sizes, respectively.

2  –  Arguments

 number

    The number of items to be allocated.

 size

    The size of each item.

3  –  Description

    The calloc function initializes the items to 0. The maximum
    amount of memory allocated at once is limited to 0xFFFFD000.

    See also malloc and realloc.

4  –  Return Values

    x                  The address of the first byte, which
                       is aligned on a quadword boundary
                       (Alpha only) or an octaword boundary
                       (Integrity servers(ONLY)) .
    NULL               Indicates an inability to allocate the space.