The wcpcpy function is the wide-character equivalent of the stpcpy function. It copies the wide character string pointed to by src, including the terminating L\0 character, to the array pointed to by dest.
The strings may not overlap.
The programmer must ensure that there is room for at least wcslen(src)+1 wide characters at dest.
wcpcpy returns a pointer to the end of the wide-character string dest, that is, a pointer to the terminating L\0 character.
This function is a GNU extension.