asio: async_write handler not called in Linux but called in Windows
Hi, I have an application that need to work on both Windows and Linux. We are using asio for network communication (boost 1.57). In this, once the connection is established with the server, the connection handler in client executes the following async calls... boost::asio::async_read_until(Socket, stream, string("\r\n"), boost::bind(&MyConnection::HandleRead, shared_from_this(), boost::asio::placeholders::error)); ... ... ... boost::asio::async_write(Socket,boost::asio::buffer(buff,len), boost::bind(&MyConnection::HandleWrite,shared_from_this(), boost::asio::placeholders::error,boost::asio::placeholders::bytes_transferred)); On Windows, the "HandleWrite" function is called as soon as the data is written. But on Linux this function never gets called!. In Linux and Windows HandleRead is getting called as expected. In bot the the case, the server receives the data properly. Is there any reason for this? Thanks, Lloyd
Further debugging the issue, I found that if I pass a small buffer (like 10KB) to write, the async_write handler (HandleWrite) is called. I was passing 128 MB of data to be written in a single async_write call. Does this has something to do with not calling the write handler? In Wondows also I am passing 128 MB buffer, but it works! On Thu, Jul 16, 2015 at 3:03 PM, Lloyd <lloydkl.tech@gmail.com> wrote:
Hi,
I have an application that need to work on both Windows and Linux. We are using asio for network communication (boost 1.57). In this, once the connection is established with the server, the connection handler in client executes the following async calls...
boost::asio::async_read_until(Socket, stream, string("\r\n"), boost::bind(&MyConnection::HandleRead, shared_from_this(), boost::asio::placeholders::error)); ... ... ... boost::asio::async_write(Socket,boost::asio::buffer(buff,len), boost::bind(&MyConnection::HandleWrite,shared_from_this(),
boost::asio::placeholders::error,boost::asio::placeholders::bytes_transferred));
On Windows, the "HandleWrite" function is called as soon as the data is written. But on Linux this function never gets called!. In Linux and Windows HandleRead is getting called as expected.
In bot the the case, the server receives the data properly. Is there any reason for this?
Thanks, Lloyd
I have enabled "BOOST_ASIO_ENABLE_HANDLER_TRACKING" and checked what is happening... The relevant and partial output is given below... This output is for a buffer of 32KB in size. @asio|1437455926.606762|9*10|socket@0xb6601154.async_send @asio|1437455926.606885|<9| @asio|1437455926.606910|>10|ec=system:0,bytes_transferred=28960 @asio|1437455926.606930|10*11|socket@0xb6601154.async_send @asio|1437455926.606940|<10| @asio|1437455926.608395|>11|ec=system:0,bytes_transferred=3808 //**** Here it enters my write handler *****// @asio|1437455926.620076|11*12|socket@0xb6601154.async_send @asio|1437455926.620211|<11| @asio|1437455926.620224|>12|ec=system:0,bytes_transferred=32768 //**** Here it enters my write handler *****// @asio|1437455926.620451|12*13|socket@0xb6601154.async_send @asio|1437455926.620486|<12| @asio|1437455926.620496|>13|ec=system:0,bytes_transferred=16464 @asio|1437455926.620505|13*14|socket@0xb6601154.async_send @asio|1437455926.620515|<13| @asio|1437455926.622322|>14|ec=system:0,bytes_transferred=16304 //**** Here it enters my write handler *****// @asio|1437455926.622549|14*15|socket@0xb6601154.async_send @asio|1437455926.622573|<14| @asio|1437455926.622588|>15|ec=system:0,bytes_transferred=5416 @asio|1437455926.622597|15*16|socket@0xb6601154.async_send @asio|1437455926.622617|<15| @asio|1437455926.622626|>16|ec=system:0,bytes_transferred=4344 @asio|1437455926.622635|16*17|socket@0xb6601154.async_send @asio|1437455926.622645|<16| @asio|1437455926.624319|>17|ec=system:0,bytes_transferred=18824 @asio|1437455926.624341|17*18|socket@0xb6601154.async_send @asio|1437455926.624354|<17| It has so much data more to be written, but the handler (18) is not getting called! In the documentation it is stated that "async_write" is a composed operation of "async_write_some". But here it seems it is using "async_send". The code works as expected in windows! I am using Ubuntu 14.4 LTS. Can anybody give some hint to debug this issue? Thanks a lot, Lloyd On Fri, Jul 17, 2015 at 1:45 PM, Lloyd <lloydkl.tech@gmail.com> wrote:
Further debugging the issue, I found that if I pass a small buffer (like 10KB) to write, the async_write handler (HandleWrite) is called. I was passing 128 MB of data to be written in a single async_write call. Does this has something to do with not calling the write handler? In Wondows also I am passing 128 MB buffer, but it works!
On Thu, Jul 16, 2015 at 3:03 PM, Lloyd <lloydkl.tech@gmail.com> wrote:
Hi,
I have an application that need to work on both Windows and Linux. We are using asio for network communication (boost 1.57). In this, once the connection is established with the server, the connection handler in client executes the following async calls...
boost::asio::async_read_until(Socket, stream, string("\r\n"), boost::bind(&MyConnection::HandleRead, shared_from_this(), boost::asio::placeholders::error)); ... ... ... boost::asio::async_write(Socket,boost::asio::buffer(buff,len), boost::bind(&MyConnection::HandleWrite,shared_from_this(),
boost::asio::placeholders::error,boost::asio::placeholders::bytes_transferred));
On Windows, the "HandleWrite" function is called as soon as the data is written. But on Linux this function never gets called!. In Linux and Windows HandleRead is getting called as expected.
In bot the the case, the server receives the data properly. Is there any reason for this?
Thanks, Lloyd
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Lloyd