This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       There is now no requirement for the implementation to support the inclusion of <malloc.h>.

       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 .

IEEE/The Open Group                                   2017                                          FREE(3POSIX)

       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  free()  function  shall cause the space pointed to by ptr to be deallocated; that is, made available
       for further allocation. If ptr is a null pointer, no action shall occur. Otherwise, if the argument  does
       not  match  a  pointer  earlier  returned  by  a  function in POSIX.1‐2008 that allocates memory as if by
       malloc(), or if the space has been deallocated by  a  call  to  free()  or  realloc(),  the  behavior  is
       undefined.

       Any use of a pointer that refers to freed space results in undefined behavior.

       No errors are defined.

       Thefollowingsectionsareinformative.

       None.

       None.

       free — free allocated memory

       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.

       None.

       The free() function shall not return a value.

calloc(), malloc(), posix_memalign(), realloc()

       The Base Definitions volume of POSIX.1‐2017, <stdlib.h>

       #include <stdlib.h>

       void free(void *ptr);