Hi I posted on this a couple of hours ago with some problems. It turned out that some of the problems I had might have been due to buggy hardware. But there is still some thing I do not understand... So, now I have reproduced some of of the problems I have with out any hardware (except from a PC). Basically I'm trying to read from a input source (in this case stdin) with a timeout. Due to the design of the existing application where this have to fit is it not possible to call run on my io_service. Here is my try so far: #include <boost/asio.hpp> #include <boost/bind.hpp> #include <boost/optional.hpp> using namespace std; void set_result( boost::optional<boost::system::error_code> * a, boost::system::error_code b ) { if( b == 0) a->reset( b ); } void receive(boost::asio::io_service & io, boost::asio::posix::stream_descriptor & stream, boost::asio::streambuf & result){ boost::optional<boost::system::error_code> timer_result; boost::optional<boost::system::error_code> read_result; boost::asio::deadline_timer timer( io ); timer.expires_from_now( boost::posix_time::milliseconds(5000) ); // allow up to 50ms of timeout for every char timer.async_wait( boost::bind(&set_result, &timer_result, _1) ); boost::asio::async_read( stream, result, boost::asio::transfer_at_least(1), boost::bind( &set_result, &read_result, _1 )); boost::system::error_code ec; while(1) { io.reset(); io.poll_one(ec); if ( read_result ) { timer.cancel(); return; } else if ( timer_result ) throw std::runtime_error("timeout"); } } void receive(boost::asio::io_service & io, boost::asio::posix::stream_descriptor & stream, size_t size, boost::asio::streambuf & result){ while( result.size() < size ) receive(io, stream, result); } int main(int argc, const char *argv[]) { boost::asio::io_service io; boost::asio::posix::stream_descriptor in(io, ::dup(STDIN_FILENO)); for(int i = 0; i < 5; i++){ std::cout << i << " Type in 4 chareters and press enter" << std::endl << std::endl; std::cout << "in> "; std::cout.flush(); try { boost::asio::streambuf buf; receive(io, in, 5, buf); std::cout << "out> "; std::copy(boost::asio::buffer_cast<const char *>(buf.data()), boost::asio::buffer_cast<const char *>(buf.data()) + buf.size(), ostream_iterator<char>(std::cout)); } catch (const std::exception & e) { std::cout << e.what() << endl; } } return 0; } At my first look, I thought that it was working, but after playing more around with the test app, I got some segmentations faults. I found that something bad happens if I wait for the first query to timeout, and then enter 5 chars the next. Here is what valgrind says: ==17848== Memcheck, a memory error detector ==17848== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al. ==17848== Using Valgrind-3.6.1 and LibVEX; rerun with -h for copyright info ==17848== Command: ./ccTalkScan ==17848== ==17848== 0 Type in 4 chareters and press enter in> ==17848== Invalid read of size 8 ==17848== at 0x546EB4A: ??? (setcontext.S:60) ==17848== by 0x425847: receive(boost::asio::io_service&, boost::asio::posix::basic_stream_descriptor<boost::asio::posix::stream_descriptor_service>&, unsigned long, boost::asio::basic_streambuf<std::allocator<char> >&) (ccTalkScan.cxx:3 20) ==17848== by 0x425982: main (ccTalkScan.cxx:334) ==17848== Address 0x7feffdf68 is not stack'd, malloc'd or (recently) free'd ==17848== ==17848== Invalid read of size 8 ==17848== at 0x546EB52: ??? (setcontext.S:63) ==17848== by 0x425847: receive(boost::asio::io_service&, boost::asio::posix::basic_stream_descriptor<boost::asio::posix::stream_descriptor_service>&, unsigned long, boost::asio::basic_streambuf<std::allocator<char> >&) (ccTalkScan.cxx:3 20) ==17848== by 0x425982: main (ccTalkScan.cxx:334) ==17848== Address 0x7feffdf58 is not stack'd, malloc'd or (recently) free'd ==17848== ==17848== Invalid read of size 8 ==17848== at 0x546EB59: ??? (setcontext.S:64) ==17848== by 0x425847: receive(boost::asio::io_service&, boost::asio::posix::basic_stream_descriptor<boost::asio::posix::stream_descriptor_service>&, unsigned long, boost::asio::basic_streambuf<std::allocator<char> >&) (ccTalkScan.cxx:320) ==17848== by 0x425982: main (ccTalkScan.cxx:334) ==17848== Address 0x7feffdf28 is not stack'd, malloc'd or (recently) free'd ==17848== ==17848== Invalid read of size 8 ==17848== at 0x546EB4A: ??? (setcontext.S:60) ==17848== by 0x5E4BD2C: (below main) (in /lib64/libc-2.12.2.so) ==17848== Address 0x7feffdfd8 is not stack'd, malloc'd or (recently) free'd ==17848== ==17848== Invalid read of size 8 ==17848== at 0x546EB52: ??? (setcontext.S:63) ==17848== by 0x5E4BD2C: (below main) (in /lib64/libc-2.12.2.so) ==17848== Address 0x7feffdfc8 is not stack'd, malloc'd or (recently) free'd ==17848== ==17848== Invalid read of size 8 ==17848== at 0x546EB59: ??? (setcontext.S:64) ==17848== by 0x5E4BD2C: (below main) (in /lib64/libc-2.12.2.so) ==17848== Address 0x7feffdf98 is not stack'd, malloc'd or (recently) free'd ==17848== timeout 1 Type in 4 chareters and press enter in> asdf ==17848== Syscall param readv(vector[...]) points to unaddressable byte(s) ==17848== at 0x5EF7A81: readv (in /lib64/libc-2.12.2.so) ==17848== by 0x42AF1C: boost::asio::detail::descriptor_ops::non_blocking_read(int, iovec*, unsigned long, boost::system::error_code&, unsigned long&) (descriptor_ops.ipp:153) ==17848== by 0x4360BF: boost::asio::detail::descriptor_read_op_base<boost::asio::mutable_buffers_1>::do_perform(boost::asio::detail::reactor_op*) (descriptor_read_op.hpp:55) ==17848== by 0x427CE4: boost::asio::detail::reactor_op::perform() (reactor_op.hpp:40) ==17848== by 0x429003: boost::asio::detail::epoll_reactor::run(bool, boost::asio::detail::op_queue<boost::asio::detail::task_io_service_operation>&) (epoll_reactor.ipp:286) ==17848== by 0x429C81: boost::asio::detail::task_io_service::do_one(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&, boost::asio::detail::task_io_service::idle_thread_info*) (task_io_service.ipp:264) ==17848== by 0x42986F: boost::asio::detail::task_io_service::poll_one(boost::system::error_code&) (task_io_service.ipp:188) ==17848== by 0x42A0C2: boost::asio::io_service::poll_one(boost::system::error_code&) (io_service.ipp:103) ==17848== by 0x4255E1: receive(boost::asio::io_service&, boost::asio::posix::basic_stream_descriptor<boost::asio::posix::stream_descriptor_service>&, boost::asio::basic_streambuf<std::allocator<char> >&) (ccTalkScan.cxx:307) ==17848== by 0x425847: receive(boost::asio::io_service&, boost::asio::posix::basic_stream_descriptor<boost::asio::posix::stream_descriptor_service>&, unsigned long, boost::asio::basic_streambuf<std::allocator<char> >&) (ccTalkScan.cxx:320) ==17848== by 0x425982: main (ccTalkScan.cxx:334) ==17848== Address 0x65ba4f0 is 0 bytes inside a block of size 512 free'd ==17848== at 0x4C25C4F: operator delete(void*) (vg_replace_malloc.c:387) ==17848== by 0x432D07: __gnu_cxx::new_allocator<char>::deallocate(char*, unsigned long) (new_allocator.h:95) ==17848== by 0x4316BF: std::_Vector_base<char, std::allocator<char>
::_M_deallocate(char*, unsigned long) (stl_vector.h:146) ==17848== by 0x42FD64: std::_Vector_base<char, std::allocator<char> ::~_Vector_base() (stl_vector.h:132) ==17848== by 0x42D6A4: std::vector<char, std::allocator<char> ::~vector() (stl_vector.h:313) ==17848== by 0x42B657: boost::asio::basic_streambuf<std::allocator<char> ::~basic_streambuf() (basic_streambuf.hpp:114) ==17848== by 0x425A77: main (ccTalkScan.cxx:336) ==17848== out> 2 Type in 4 chareters and press enter
in> timeout 3 Type in 4 chareters and press enter in> timeout 4 Type in 4 chareters and press enter in> timeout ==17848== ==17848== HEAP SUMMARY: ==17848== in use at exit: 168 bytes in 3 blocks ==17848== total heap usage: 65 allocs, 62 frees, 22,246 bytes allocated ==17848== ==17848== LEAK SUMMARY: ==17848== definitely lost: 0 bytes in 0 blocks ==17848== indirectly lost: 0 bytes in 0 blocks ==17848== possibly lost: 0 bytes in 0 blocks ==17848== still reachable: 168 bytes in 3 blocks ==17848== suppressed: 0 bytes in 0 blocks ==17848== Rerun with --leak-check=full to see details of leaked memory ==17848== ==17848== For counts of detected and suppressed errors, rerun with: -v ==17848== Use --track-origins=yes to see where uninitialised values come from ==17848== ERROR SUMMARY: 27 errors from 9 contexts (suppressed: 4 from 4) I have tried different things to fix, but I that I might have mis understood a thing or two here. So some help would be most appreciated. -- Allan W. Nielsen