PROLOG

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of
       this interface may differ (consult 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 functionality described on this reference page is aligned with the ISO C standard. Any
       conflict between the requirements described here and the ISO C standard is  unintentional.
       This volume of POSIX.1‐2008 defers to the ISO C standard.

       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 reallocated). 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 POSIX.1‐2008, <stdlib.h>

COPYRIGHT

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2013 Edition, Standard for Information Technology  --  Portable  Operating  System
       Interface  (POSIX),  The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc  and  The  Open  Group.   (This  is
       POSIX.1-2008  with  the  2013  Technical  Corrigendum  1  applied.)  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.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are most  likely  to  have
       been  introduced  during  the conversion of the source files to man page format. To report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .