long osdFileWrite(OSD_File *file, char *buffer,unsigned long len)
The memory area pointed to by buffer
should be valid for the number of bytes specified by len.
After osdFileWrite() the file pointer location is incremented by the
actual number of bytes written.
Returns the actual number of bytes written. This may be less than
len if the file system becomes full of the write is interrupted.
| file | the file to which to write |
| buffer | a pointer to data to be written |
| len | the number of bytes to write |