when I use strlcpy function in c the compilor give me an error

strlcpy() ist not a standard C function.

You might like to use strncpy() or propably also memcpy() instead.

Add this code to your code:

#ifndef HAVE_STRLCAT
/*
 * '_cups_strlcat()' - Safely concatenate two strings.
 */

size_t                  /* O - Length of string */
strlcat(char       *dst,        /* O - Destination string */
              const char *src,      /* I - Source string */
          size_t     size)      /* I - Size of destination string buffer */
{
  size_t    srclen;         /* Length of source string */
  size_t    dstlen;         /* Length of destination string */


 /*
  * Figure out how much room is left...
  */

  dstlen = strlen(dst);
  size   -= dstlen + 1;

  if (!size)
    return (dstlen);        /* No room, return immediately... */

 /*
  * Figure out how much room is needed...
  */

  srclen = strlen(src);

 /*
  * Copy the appropriate amount...
  */

  if (srclen > size)
    srclen = size;

  memcpy(dst + dstlen, src, srclen);
  dst[dstlen + srclen] = '\0';

  return (dstlen + srclen);
}
#endif /* !HAVE_STRLCAT */

#ifndef HAVE_STRLCPY
/*
 * '_cups_strlcpy()' - Safely copy two strings.
 */

size_t                  /* O - Length of string */
strlcpy(char       *dst,        /* O - Destination string */
              const char *src,      /* I - Source string */
          size_t      size)     /* I - Size of destination string buffer */
{
  size_t    srclen;         /* Length of source string */


 /*
  * Figure out how much room is needed...
  */

  size --;

  srclen = strlen(src);

 /*
  * Copy the appropriate amount...
  */

  if (srclen > size)
    srclen = size;

  memcpy(dst, src, srclen);
  dst[srclen] = '\0';

  return (srclen);
}
#endif /* !HAVE_STRLCPY */

then, you can use it. enjoy it.

undefined reference to `strlcpy'

This happens when the linker (collect2 if you are using gcc) can not find the definition of the function it complains about (not the declaration or prototype, but the definition, where the function's code is defined).

In your case it may happen because there is no shared object or library with strlcpy's code to link against. If you are sure there is a library with the code and you want to link against it, consider specifying the path to the library with the -L<path_to_library> parameter passed to the compiler.