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STRCPY(3)		    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 (includ-
       ing 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	termi-
       nated.

       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 follow-
       ing 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  run-
       ning 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	14.3			 June 6, 2018			     STRCPY(3)

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