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NAME

       strcpy, strncpy - copy a string

SYNOPSIS

       #include <string.h>

       char *strcpy(char *dest, const char *src);

       char *strncpy(char *dest, const char *src, size_t n);

DESCRIPTION

       The  strcpy()  function  copies the string pointed to by src, including
       the terminating null byte ('\0'), to the buffer  pointed  to  by  dest.
       The  strings  may  not overlap, and the destination string dest must be
       large enough to receive the copy.

       The strncpy() function is similar, except that at most n bytes  of  src
       are  copied.  Warning: If there is no null byte among the first n bytes
       of src, the string placed in dest will not be null-terminated.

       If the length of src is less than n, strncpy() pads  the  remainder  of
       dest with null bytes.

       A simple implementation of strncpy() might be:

           char*
           strncpy(char *dest, const char *src, size_t n){
               size_t i;

               for (i = 0 ; i < n && src[i] != '\0' ; i++)
                   dest[i] = src[i];
               for ( ; i < n ; i++)
                   dest[i] = '\0';

               return dest;
           }

RETURN VALUE

       The   strcpy()   and  strncpy()  functions  return  a  pointer  to  the
       destination string dest.

CONFORMING TO

       SVr4, 4.3BSD, C89, C99.

NOTES

       Some programmers consider strncpy() to be inefficient and error  prone.
       If  the  programmer knows (i.e., includes code to test!)  that the size
       of dest is greater than the length of src, then strcpy() can be used.

       If there is no terminating null byte in the first n characters of  src,
       strncpy()  produces  an unterminated string in dest.  Programmers often
       prevent this mistake by forcing termination as follows:

           strncpy(buf, str, n);
           if (n > 0)
               buf[n - 1]= '\0';

BUGS

       If the destination string of a  strcpy()  is  not  large  enough,  then
       anything  might  happen.   Overflowing fixed-length string buffers is a
       favorite cracker technique for taking complete control of the  machine.
       Any  time  a  program  reads  or copies data into a buffer, the program
       first  needs  to  check  that  there's  enough  space.   This  may   be
       unnecessary  if  you  can  show  that  overflow  is  impossible, but be
       careful: programs can get changed over time, in ways that may make  the
       impossible possible.

SEE ALSO

       bcopy(3),  memccpy(3),  memcpy(3),  memmove(3),  stpcpy(3),  string(3),
       strdup(3), wcscpy(3), wcsncpy(3)

COLOPHON

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       description  of  the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.