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

NAME
     stpcpy, strcpy, strncpy -- copy strings

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <string.h>

     char *
     stpcpy(char *s1, const char *s2);

     char *
     strcpy(char *restrict s1, const char *restrict s2);

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

DESCRIPTION
     The stpcpy() and strcpy() functions copy the string s2 to s1 (including the terminating `\0' charac-ter). character).
     ter).

     The strncpy() function copies at most n characters from s2 into s1.  If s2 is less than n characters
     long, the remainder of s1 is filled with `\0' characters.  Otherwise, s1 is not terminated.

     The source and destination strings should not overlap, as the behavior is undefined.

RETURN VALUES
     The strcpy() and strncpy() functions return s1.  The stpcpy() function returns a pointer to the termi-nating terminating
     nating `\0' character of s1.

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));

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

SECURITY CONSIDERATIONS
     The strcpy() function is easily misused in a manner which enables malicious 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 strcpy() and strncpy() functions conform to ISO/IEC 9899:1990 (``ISO C90'').  The stpcpy() function
     is an MS-DOS and GNUism.  The stpcpy() function conforms to no standard.

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

BSD                                            August 9, 2001                                            BSD