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



PPRROOLLOOGG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.


NNAAMMEE
       calloc -- a memory allocator

SSYYNNOOPPSSIISS
       #include <stdlib.h>

       void *calloc(size_t _n_e_l_e_m, size_t _e_l_s_i_z_e);

DDEESSCCRRIIPPTTIIOONN
       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 _c_a_l_l_o_c() function shall allocate unused space for an array of _n_e_l_e_m
       elements each of whose size in bytes is _e_l_s_i_z_e.  The space shall be
       initialized to all bits 0.

       The order and contiguity of storage allocated by successive calls to
       _c_a_l_l_o_c() 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.

RREETTUURRNN VVAALLUUEE
       Upon successful completion with both _n_e_l_e_m and _e_l_s_i_z_e non-zero,
       _c_a_l_l_o_c() shall return a pointer to the allocated space. If either _n_e_l_e_m
       or _e_l_s_i_z_e is 0, then either a null pointer or a unique pointer value
       that can be successfully passed to _f_r_e_e() shall be returned. Otherwise,
       it shall return a null pointer and set _e_r_r_n_o to indicate the error.

EERRRROORRSS
       The _c_a_l_l_o_c() function shall fail if:

       EENNOOMMEEMM Insufficient memory is available.

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       There is now no requirement for the implementation to support the
       inclusion of _<_m_a_l_l_o_c_._h_>.

RRAATTIIOONNAALLEE
       None.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _f_r_e_e(), _m_a_l_l_o_c(), _r_e_a_l_l_o_c()

       The Base Definitions volume of POSIX.1-2008, <<ssttddlliibb..hh>>

CCOOPPYYRRIIGGHHTT
       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 .



IEEE/The Open Group                  2013                            CALLOC(3)
