1CALLOC(3P) POSIX Programmer's Manual CALLOC(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
13 calloc — a memory allocator
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16 #include <stdlib.h>
17 void *calloc(size_t nelem, size_t elsize);
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21 The functionality described on this reference page is aligned with the
22 ISO C standard. Any conflict between the requirements described here
23 and the ISO C standard is unintentional. This volume of POSIX.1‐2008
24 defers to the ISO C standard.
25 The calloc() function shall allocate unused space for an array of nelem
27 elements each of whose size in bytes is elsize. The space shall be
28 initialized to all bits 0.
29 The order and contiguity of storage allocated by successive calls to
31 calloc() is unspecified. The pointer returned if the allocation suc‐
32 ceeds shall be suitably aligned so that it may be assigned to a pointer
33 to any type of object and then used to access such an object or an
34 array of such objects in the space allocated (until the space is
35 explicitly freed or reallocated). Each such allocation shall yield a
36 pointer to an object disjoint from any other object. The pointer
37 returned shall point to the start (lowest byte address) of the allo‐
38 cated space. If the space cannot be allocated, a null pointer shall be
39 returned. If the size of the space requested is 0, the behavior is
40 implementation-defined: the value returned shall be either a null
41 pointer or a unique pointer.
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44 Upon successful completion with both nelem and elsize non-zero, cal‐
45 loc() shall return a pointer to the allocated space. If either nelem or
46 elsize is 0, then either a null pointer or a unique pointer value that
47 can be successfully passed to free() shall be returned. Otherwise, it
48 shall return a null pointer and set errno to indicate the error.
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51 The calloc() function shall fail if:
52 ENOMEM Insufficient memory is available.
54 The following sections are informative.
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58 None.
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61 There is now no requirement for the implementation to support the
62 inclusion of <malloc.h>.
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65 None.
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68 None.
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71 free(), malloc(), realloc()
72 The Base Definitions volume of POSIX.1‐2008, <stdlib.h>
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76 Portions of this text are reprinted and reproduced in electronic form
77 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
78 -- Portable Operating System Interface (POSIX), The Open Group Base
79 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
80 cal and Electronics Engineers, Inc and The Open Group. (This is
81 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
82 event of any discrepancy between this version and the original IEEE and
83 The Open Group Standard, the original IEEE and The Open Group Standard
84 is the referee document. The original Standard can be obtained online
85 at http://www.unix.org/online.html .
86 Any typographical or formatting errors that appear in this page are
88 most likely to have been introduced during the conversion of the source
89 files to man page format. To report such errors, see https://www.ker‐
90 nel.org/doc/man-pages/reporting_bugs.html .
91IEEE/The Open Group 2013 CALLOC(3P)