PROLOG

       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

       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.1‐2017 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: either a null pointer shall be
       returned, or the behavior shall be as if the size were some non-zero  value,  except  that
       the behavior is undefined if the returned pointer is used to access an object.

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 shall be returned and errno may be  set  to  an  implementation-defined
           value, or

        *  A  pointer to the allocated space shall be returned. The application shall ensure that
           the pointer is not used to access an object.

       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.1‐2017, <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1-2017,  Standard  for  Information Technology -- Portable Operating System Interface
       (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C)  2018  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.opengroup.org/unix/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 .