[haiku-bugs] Re: [Haiku] #8789: read doesn't work for serial communication (neither bash's nor BSerialPort::Read())
- From: "ttcoder" <trac@xxxxxxxxxxxx>
- Date: Tue, 07 Aug 2012 20:36:00 -0000
#8789: read doesn't work for serial communication (neither bash's nor
BSerialPort::Read())
---------------------------+----------------------------
Reporter: dsuden | Owner: mmlr
Type: bug | Status: new
Priority: normal | Milestone: R1
Component: Drivers/USB | Version: R1/Development
Resolution: | Keywords:
Blocked By: | Blocking:
Has a Patch: 0 | Platform: x86
---------------------------+----------------------------
Comment (by ttcoder):
(sorry, meant to say BSerialPort::WaitForInput()). Anyway no luck, it did
not save the day.. Findings:
- WaitForInput() seems to be unusable, no matter the use scenario it
returns '''0x80000005: Invalid Argument'''
- Looking at the headers I noticed there exists a NumCharsAvailable() too,
but it's marked as [http://cgit.haiku-
os.org/haiku/tree/src/kits/device/SerialPort.cpp#n396 TODO: implement]
- Read() continues to work fairly well... but synchronously (i.e.
blocking, even if the port is configured as SetBlocking( false))
Now for the ''weird'' one: there seems to be a side-effect of the driver
on my userland code of some sort; namely, an if(variable>=2) statement in
my code is not executed despite the variable being == 2, unless I make
neutral changes to the code adding printf()s;
Rephrasing:
- the first line looks like this:
{{{
printf("USB-serial test-case running (argc=%d)\n", argc);
}}}
and correctly prints "argc=2" when I pass an argument.
YET an if() at the end of main() looking like this:
{{{
if( argc >= 2 )
{
char buf[128] = { 0 };
puts( "Enter string to send to BT box (e.g. *0U or
*0111 or *011A ...), followed by <enter> :" );
}}}
is never entered... until after I add some tracing printf()s higher-up in
the program. Does not look like memory corruption per se. I've looked for
beginner-style mistakes (we're all subject to misplaced semicolons when
tired eh? :-) in my code and there's none. Go figure. Not ruling out a
mis-communication between me & Dane though (it occured on his setup).
Another possible theory: maybe the if() ''is'' entered but the puts()
fails to send text to Terminal for some reason, as a side-effect of all
the ioctl()s being executed behind the scenes, and these ioctl()s wrongs
are righted only if peppering my code with printf() calls...
Anyway bottom-line for now, all the doors are closing on me, except the
rewrite-my-code-to-be-synchronous one. Dang.
--
Ticket URL: <http://dev.haiku-os.org/ticket/8789#comment:12>
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