Question

Is there a way to cancel a pending operation (without disconnect) or set a timeout for the boost library functions?

I.e. I want to set a timeout on blocking socket in boost asio?

socket.read_some(boost::asio::buffer(pData, maxSize), error_);

Example: I want to read some from the socket, but I want to throw an error if 10 seconds have passed.

Answer 1

Under Linux/BSD the timeout on I/O operations on sockets is directly supported by the operating system. The option can be enabled via setsocktopt(). I don’t know if boost::asio provides a method for setting it or exposes the socket scriptor to allow you to directly set it — the latter case is not really portable.

For a sake of completeness here’s the description from the man page:

SO_RCVTIMEO and SO_SNDTIMEO

          Specify the receiving or sending  timeouts  until  reporting  an           error.  The argument is a struct timeval.  If an input or output           function blocks for this period of time, and data has been  sent           or  received,  the  return  value  of  that function will be the           amount of data transferred; if no data has been transferred  and           the  timeout has been reached then -1 is returned with errno set           to EAGAIN or EWOULDBLOCK just as if the socket was specified  to           be  non-blocking.   If  the timeout is set to zero (the default)           then the operation  will  never  timeout.   Timeouts  only  have           effect  for system calls that perform socket I/O (e.g., read(2),           recvmsg(2), send(2), sendmsg(2)); timeouts have  no  effect  for           select(2), poll(2), epoll_wait(2), etc.