PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

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

PROLOG         top

       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         top

       malloc — a memory allocator

SYNOPSIS         top

       #include <stdlib.h>

       void *malloc(size_t size);

DESCRIPTION         top

       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         top

       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         top

       The malloc() function shall fail if:

       ENOMEM Insufficient storage space is available.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       calloc(3p), free(3p), getrlimit(3p), posix_memalign(3p), realloc(3p)

       The Base Definitions volume of POSIX.1‐2008, stdlib.h(0p)

COPYRIGHT         top

       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(3P)

Pages that refer to this page: stdlib.h(0p)calloc(3p)fmemopen(3p)free(3p)getcwd(3p)getrlimit(3p)hcreate(3p)posix_memalign(3p)putenv(3p)realloc(3p)