STRCPY(3)              FreeBSD Library Functions Manual              STRCPY(3)

NAME
     stpcpy, stpncpy, strcpy, strncpy - copy strings

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <string.h>

     char *
     stpcpy(char * restrict dst, const char * restrict src);

     char *
     stpncpy(char * restrict dst, const char * restrict src, size_t len);

     char *
     strcpy(char * restrict dst, const char * restrict src);

     char *
     strncpy(char * restrict dst, const char * restrict src, size_t len);

DESCRIPTION
     The strcpy() and stpcpy() functions copy the string src to dst (including
     the terminating `\0' character.)

     The strncpy() and stpncpy() functions copy at most len characters from
     src into dst.  If src is less than len characters long, the remainder of
     dst is filled with `\0' characters.  Otherwise, dst is not terminated.

     For all of strcpy(), strncpy(), stpcpy(), and stpncpy(), the result is
     undefined if src and dst overlap.

RETURN VALUES
     The strcpy() and strncpy() functions return dst.  The stpcpy() and
     stpncpy() functions return a pointer to the terminating `\0' character of
     dst.  If stpncpy() does not terminate dst with a NUL character, it
     instead returns a pointer to dst[n] (which does not necessarily refer to
     a valid memory location.)

EXAMPLES
     The following sets chararray to "abc\0\0\0":

           char chararray[6];

           (void)strncpy(chararray, "abc", sizeof(chararray));

     The following sets chararray to "abcdef":

           char chararray[6];

           (void)strncpy(chararray, "abcdefgh", sizeof(chararray));

     Note that it does not NUL terminate chararray because the length of the
     source string is greater than or equal to the length argument.

     The following copies as many characters from input to buf as will fit and
     NUL terminates the result.  Because strncpy() does not guarantee to NUL
     terminate the string itself, this must be done explicitly.

           char buf[1024];

           (void)strncpy(buf, input, sizeof(buf) - 1);
           buf[sizeof(buf) - 1] = '\0';

     This could be better achieved using strlcpy(3), as shown in the following
     example:

           (void)strlcpy(buf, input, sizeof(buf));

SEE ALSO
     bcopy(3), memccpy(3), memcpy(3), memmove(3), strlcpy(3), wcscpy(3)

STANDARDS
     The strcpy() and strncpy() functions conform to ISO/IEC 9899:1990
     ("ISO C90").  The stpcpy() and stpncpy() functions conform to IEEE Std
     1003.1-2008 ("POSIX.1").

HISTORY
     The stpcpy() function first appeared in FreeBSD 4.4, and stpncpy() was
     added in FreeBSD 8.0.

SECURITY CONSIDERATIONS
     All of the functions documented in this manual page are easily misused in
     a manner which enables malicious users to arbitrarily change a running
     program's functionality through a buffer overflow attack.

     It is strongly suggested that the strlcpy() function be used in almost
     all cases.

     For some, but not all, fixed-length records, non-terminated strings may
     be both valid and desirable.  In that specific case, the strncpy()
     function may be most sensible.

FreeBSD 13.1-RELEASE-p6          June 6, 2018          FreeBSD 13.1-RELEASE-p6