The function writes into a bin-file contents of a structure passed as a parameter, starting from the current position of the file pointer.
[in] File descriptor returned by FileOpen().
[in] Number of bytes that you want to record. If size is not specified or the specified number of bytes is greater than the size of the structure, the entire structure is written.
If successful the function returns the number of bytes written. The file pointer is shifted by the same number of bytes.