Hello All !
I was reading Linux Device Drivers , by
A.Rubini and found the below lines on page 71
near the end .
" The only real operation performed on the
device is truncating it to a length of zero when
the device is opened for writing. This is
performed because, by design, overwriting a pscull
device with a shorter file results in a shorter
device data area. This is similar to the way
opening a regular file for writing truncates it to
zero length. The operation does nothing if the
device is opened for reading. "
As said above in the last lines , I tried
the open system call on a regular file ,with
O_WRONLY option , without doing any further
operations . I was expecting the regular file to
truncate to zero after the open call as said above,
but I found that the regular file is
intact .
Can anybody please explain ?
Or maybe I have not understood the above lines
properly .
Thanks in advance .
Regards !
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