c/string/wide/wcscat

@1@ Appends a copy of the wide string pointed to by to the end of the wide string pointed to by. The wide character replaces the null terminator at the end of. The resulting wide string is null-terminated. The behavior is undefined if the destination array is not large enough for the contents of both and  and the terminating null wide character. The behavior is undefined if the strings overlap. @2@ Same as, except that it may clobber the rest of the destination array (from the last character written to ) with unspecified values and that the following errors are detected at runtime and call the currently installed constraint handler function:
 * or is a null pointer
 * is zero or greater than
 * there is no null terminator in the first wide characters of
 * truncation would occur (the available space at the end of would not fit every wide character, including the null terminator, of )
 * overlap would occur between the source and the destination strings

Return value
@1@ returns a copy of @2@ returns zero on success, returns non-zero on error. Also, on error, writes to  (unless  is a null pointer or  is zero or greater than ).