MALLOC(3P)                                          POSIX Programmer's Manual                                         MALLOC(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
       malloc - a memory allocator

SYNOPSIS
       #include <stdlib.h>

       void *malloc(size_t size);


DESCRIPTION
       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  alloca-
       tion  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(), 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                                                    MALLOC(3P)