size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE
Writes data from the array pointed to by ptr to the given stream. It writes nmemb number of elements of
size size. The total number of bytes written is (size*nmemb).
On success the number of elements writen is returned. On error the total number of elements
successfully writen (which may be zero) is returned.