c/string/wide/wcsncpy

@1@ Copies at most characters of the wide string pointed to by  (including the terminating null wide character) to wide character array pointed to by. @@ If is reached before the entire string  was copied, the resulting wide character array is not null-terminated. @@ If, after copying the terminating null wide character from, is not reached, additional null wide characters are written to  until the total of  characters have been written. @@ If the strings overlap, the behavior is undefined. @2@ Same as, except that the function does not continue writing zeroes into the destination array to pad up to , it stops after writing the terminating null character (if there was no null in the source, it writes one at and then stops). Also, the following errors are detected at runtime and call the currently installed constraint handler function:
 * or is a null pointer
 * or is zero or greater than
 * is greater or equal, but is less or equal , in other words, truncation would occur
 * 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 ) and may clobber the rest of the destination array with unspecified values.