destination
Pointer to the destination array where the content is to be copied.
source
Pointer to the source of data to be copied.
num
Number of bytes to copy.
size_t is an unsigned integral type.
num actually is number of byte pair (one wchar_t)!
Copy block of wide characters
Copies the values of num elements of type wchar_t from the location pointed by source to the location pointed by destination.
Yes, rather than saying "Number of bytes to copy", it should rather say "Number of elements to copy" (or the like). Rather than posting here, though, go down to the bottom of the page and click the "Spotted an error? contact us" hyperlink.