CALLOC(3P)                                          POSIX Programmer's Manual                                         CALLOC(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       calloc - a memory allocator

SYNOPSIS
       #include <stdlib.h>

       void *calloc(size_t nelem, size_t elsize);


DESCRIPTION
       The  calloc()  function shall allocate unused space for an array of nelem elements each of whose size in bytes is elsize.
       The space shall be initialized to all bits 0.

       The order and contiguity of storage allocated by successive calls to calloc() is unspecified. The pointer returned if the
       allocation succeeds shall be suitably aligned so that it may be assigned to a pointer to any type of object and then used
       to access such an object or an array of such objects in the space allocated (until the space is explicitly freed or real-
       located).  Each  such  allocation shall yield a pointer to an object disjoint from any other object. The pointer returned
       shall point to the start (lowest byte address) of the allocated space. If the space cannot be allocated, a  null  pointer
       shall  be  returned.  If the size of the space requested is 0, the behavior is implementation-defined: the value returned
       shall be either a null pointer or a unique pointer.

RETURN VALUE
       Upon successful completion with both nelem and elsize non-zero, calloc() shall return a pointer to the  allocated  space.
       If  either  nelem or elsize is 0, then either a null pointer or a unique pointer value that can be successfully passed to
       free() shall be returned. Otherwise, it shall return a null pointer  and set errno to indicate the error.

ERRORS
       The calloc() function shall fail if:

       ENOMEM Insufficient memory is available.


       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       There is now no requirement for the implementation to support the inclusion of <malloc.h>.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       free(), malloc(), realloc(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdlib.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy  between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group
       Standard  is  the  referee   document.   The   original   Standard   can   be   obtained   online   at   http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                    CALLOC(3P)