STRCPY(3) BSD Library Functions Manual STRCPY(3)

NAME
     ssttrrccppyy, ssttrrnnccppyy - copy strings

LLIIBBRRAARRYY
     Standard C Library (libc, -lc)

SYNOPSIS
     ##iinncclluuddee <>

     char *
     ssttppccppyy(char *dst, const char *src);

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

     char *
     ssttrrnnccppyy(char * restrict dst, const char * restrict src, sizet len);

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

     The ssttrrnnccppyy() function copies 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.

RETURN VALUES
     The ssttrrccppyy() and ssttrrnnccppyy() functions return dst.  The ssttppccppyy() function
     returns a pointer to the terminating `\0' character of dst.

EEXXAAMMPPLLEESS
     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 ssttrrnnccppyy() 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));

     Note that because strlcpy(3) is not defined in any standards, it should
     only be used when portability is not a concern.

SSEECCUURRIITTYY CCOONNSSIIDDEERRAATTIIOONNSS
     The ssttrrccppyy() function is easily misused in a manner which enables mali-
     cious users to arbitrarily change a running program's functionality
     through a buffer overflow attack.  (See the FSA and EXAMPLES.)

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

STANDARDS     The ssttrrccppyy() and ssttrrnnccppyy() functions conform to ISO/IEC 9899:1990
     (``ISO C90'').  The ssttppccppyy() function is an MS-DOS and GNUism.  The
     ssttppccppyy() function conforms to no standard.

HISTORY     The ssttppccppyy() function first appeared in FreeBSD 4.4, coming from
     1998-vintage Linux.

BSD                             August 9, 2001                             BSD