On Wed, 02 Sep, at 06:31:36AM, Kweh Hock Leong wrote:

I have done an experiment on that by using the misc char device file note.
I included the flush() callback function to the fops. In flush(), I put a printk()
and return -EINVAL. When I perform "cat XXX > /dev/XXX" on Intel Quark
Galileo platform, I found that the flush() is not just being called at file
close, it will also being called before the file write. And the error return, that I
forced in the flush(), does not show up at shell terminal. This is the reason that
I did not follow James recommendation and figure out to do it at write().

OK, that's interesting. Which cat tool is included with the Quark BSP?
 
-- 
Matt Fleming, Intel Open Source Technology Center