Re: [Boost-users] iostreams and serial ports help

Jonathan - thank you, that's helped massively. I now have a serial_device type along the lines you described :-) Bob - thanks for the asio suggestion - I decided that it wasn't quite what I'm looking for though. Eric - I realised I actually configure the serial port as a blocking device so it should be fine. My final (I hope!) problem is in using a stream. I cannot compile a program creating a stream object templated for my serial device: #include #include "serial_device.h"

int main(void) { boost::iostreams::stream s; }

Compiling that with g++ 3.3.3 gives: test-stream.cpp: In function `int main()':

test-stream.cpp:5: error: invalid use of template `template struct boost::iostreams::stream' test-stream.cpp:5: error: syntax error before `;' token

This is with Boost 1.34.1 Can any of you shed any light on this please?! Thanks for all the help so far :-) --rob On Jan 21, 2008 3:09 PM, Eric MALENFANT wrote:

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Rob Desbois, le 18 janvier 2008 08:02:

> > After trying to compile I realised that a SeekableDevice > provides read, write and seek functions, nothing else. > Am I seriously misunderstanding the point of boost::iostreams?

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On Jan 18, 2008 6:46 PM, Eric MALENFANT wrote:

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A file_descriptor only implements the Device concept, it not an std::iostream. If you want an std::iostream, you wrap the Device in a boost::iostreams::stream which, as stated in its documentation: "performs i/o by delegating to a contained Device", and "derives from a specialization of std::basic_istream, std::basic_ostream or std::basic_iostream, depending on whether the underlying Device models Source, Sink or both."

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Rob Desbois, le 18 janvier 2008 13:58:

Are you able to comment on whether I 'should' be doing this as regards the non-blocking and non-seekable nature of a serial port?

The "seekability" should not be a problem. You could define a BidirectionalDevice as Jonathan suggests in another message. If you only need read (or write), you could even just define a Source (or Sink).

The "blocking" side of things may be more trouble, depending on your needs. Boost.Iostreams offers minimal support for non-blocking strings: boost::iostreams::char_traits::would_block() can be used to indicate that a read or write attempt was interrupted but, unless I missed something, nothing allows the caller to wait for the blocking condition to be removed (like select() allows for non-blocking sockets, for example), so the caller has to poll the stream. As suggested by Bob Warren, Boost.Asio may offer an interesting alternative.

Éric Malenfant --------------------------------------------- Amateur programmers think there are 1000 bytes in a kilobyte; Real Programmers think there are 1024 meters in a kilometer. _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

-- Rob Desbois Eml: rob.desbois@gmail.com Tel: 07946 705987 "There's a whale there's a whale there's a whale fish" he cried, and the whale was in full view. ...Then ooh welcome. Ahhh. Ooh mug welcome.