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

       stpncpy, strncpy — copy fixed length string, returning a pointer to the array end

SYNOPSIS

       #include <string.h>

       char *stpncpy(char *restrict s1, const char *restrict s2, size_t n);
       char *strncpy(char *restrict s1, const char *restrict s2, size_t n);

DESCRIPTION

       For  strncpy():  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  stpncpy() and strncpy() functions shall copy not more than n bytes (bytes that follow
       a NUL character are not copied) from the array pointed to by s2 to the array pointed to by
       s1.

       If  the  array  pointed  to by s2 is a string that is shorter than n bytes, NUL characters
       shall be appended to the copy in the array pointed to by s1, until  n  bytes  in  all  are
       written.

       If copying takes place between objects that overlap, the behavior is undefined.

RETURN VALUE

       If  a NUL character is written to the destination, the stpncpy() function shall return the
       address of the first such NUL character.  Otherwise, it shall return &s1[n].

       The strncpy() function shall return s1.

       No return values are reserved to indicate an error.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       Applications must provide the space in s1 for the n bytes to be transferred,  as  well  as
       ensure that the s2 and s1 arrays do not overlap.

       Character   movement   is   performed  differently  in  different  implementations.  Thus,
       overlapping moves may yield surprises.

       If there is no NUL character byte in the first n bytes of the array pointed to by s2,  the
       result is not null-terminated.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       strcpy(), wcsncpy()

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