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



PROLOG
       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.


NAME
       malloc -- a memory allocator

SYNOPSIS
       #include <stdlib.h>

       void *malloc(size_t size);

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 malloc() function shall allocate unused space for an object whose
       size in bytes is specified by size and whose value is unspecified.

       The order and contiguity of storage allocated by successive calls to
       malloc() 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 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 points 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 size not equal to 0, malloc() shall
       return a pointer to the allocated space. If size is 0, either a null
       pointer or a unique pointer 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 malloc() function shall fail if:

       ENOMEM Insufficient storage space is available.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       calloc(), free(), getrlimit(), posix__memalign(), 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 .



IEEE/The Open Group                  2013                            MALLOC(3)
