[argyllcms] Re: ubuntu-10.10-desktop-amd64: dispcal -D5 -? hangs
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 26 Apr 2011 12:47:24 +1000
Gerhard Fuernkranz wrote:
you can use pass the O_NONBLOCK flag to open() in order to avoid that it
blocks.
Hi Gerhard,
yes I think I'll add that to the code as a simple fix for
Martin's problem.
Using O_NONBLOCK is also a prerequisite for turning turn on the CLOCAL
flag, because tcsetattr() requires an open file descriptor. Take care
however, that subsequent read() and write() calls will be non-blocking
too, when the tty was opened with O_NONBLOCK (e.g. read() would then
immediately return -1, with errno==EAGAIN, if no buffered received data
are available for immediate retrieval, and not wait for data).
At the moment I'm simply seeing if the port can be opened as
a way to filter out all the non-existent or unusable /dev/tty's.
can't be locked). IMO most program accessing serial ports use UCCP-style
lock files (residing in the directory /var/lock/ on Linux, e.g.
/var/lock/LCK..tty<XX>). See
http://docs.freebsd.org/info/uucp/uucp.info.UUCP_Lock_Files.html.
Hmm. A complication I'm not dealing with at the moment. Thanks
for pointing it out.
Graeme.
Other related posts:
