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

       This version is  aligned  with  the  ISO C  standard;  this  does  not  affect  compatibility  with  XPG3
       applications. Reliable error detection by this function was never guaranteed.

       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                                        STRCAT(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  strcat()  function shall append a copy of the string pointed to by s2 (including the terminating NUL
       character) to the end of the string pointed to by  s1.   The  initial  byte  of  s2  overwrites  the  NUL
       character  at  the  end  of  s1.   If  copying  takes place between objects that overlap, the behavior is
       undefined.

       No errors are defined.

       Thefollowingsectionsareinformative.

       None.

       None.

       strcat — concatenate two strings

       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 strcat() function shall return s1; no return value is reserved to indicate an error.

strncat()

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

       #include <string.h>

       char *strcat(char *restrict s1, const char *restrict s2);