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

       None.

       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                                       STRNCMP(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  strncmp()  function  shall  compare not more than n bytes (bytes that follow a NUL character are not
       compared) from the array pointed to by s1 to the array pointed to by s2.

       The sign of a non-zero return value is determined by the sign of the difference between the values of the
       first pair of bytes (both interpreted as type unsignedchar) that differ in the strings being compared.

       No errors are defined.

       Thefollowingsectionsareinformative.

       None.

       None.

       strncmp — compare part of 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.

       Upon successful completion, strncmp() shall return an integer greater than, equal to, or less than 0,  if
       the  possibly null-terminated array pointed to by s1 is greater than, equal to, or less than the possibly
       null-terminated array pointed to by s2 respectively.

strcmp()

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

       #include <string.h>

       int strncmp(const char *s1, const char *s2, size_t n);