[英]Why doesn't boost::asio::ip::udp::socket::receive_from throw interruption exception in Windows?
volatile std::sig_atomic_t running = true;
int main()
{
boost::asio::thread_pool tpool;
boost::asio::signal_set signals(tpool, SIGINT, SIGTERM);
signals.async_wait([](auto && err, int) { if (!err) running = false; });
while(running)
{
std::array<std::uint8_t, 1024> data;
socket.recieve_from(boost::asio::buffer(data), ....); // (1)
// calc(data);
}
return 0;
}
If my code is blocked in the (1) line in Linux and I try raise the signal, for example, with htop
then the line (1) throws exception about the interruption but in Windows it doesn't.如果我的代码在 Linux 的 (1) 行中被阻止,并且我尝试使用
htop
提高信号,那么 (1) 行会引发有关中断的异常,但在 Windows 中不会。 The problem in what I don't know how to exit the application.我不知道如何退出应用程序的问题。
What needs to do my program works equally in both OSs?我的程序需要做什么才能在两个操作系统中同样工作? Thanks.
谢谢。
Use Windows 10 (msvc 17), Debian 11 (gcc-9), Boost 1.78.使用 Windows 10 (msvc 17)、Debian 11 (gcc-9)、Boost 1.78。
Regardless of the question how you "raise the signal" on Windows there's the basic problem that you're relying on OS specifics to cancel a synchronous operation.无论您如何在 Windows 上“发出信号”,基本问题是您依赖操作系统细节来取消同步操作。
Cancellation is an ASIO feature, but only for asynchronous operations.取消是一项 ASIO 功能,但仅适用于异步操作。 So, consider:
所以,考虑:
signals.async_wait([&socket](auto&& err, int) {
if (!err) {
socket.cancel();
}
});
Simplifying without a thread_pool gives eg:没有 thread_pool 的简化给出了例如:
#define BOOST_ASIO_ENABLE_HANDLER_TRACKING 1
#include <boost/asio.hpp>
namespace asio = boost::asio;
using asio::ip::udp;
using boost::system::error_code;
struct Program {
Program(asio::any_io_executor executor)
: signals_{executor, SIGINT, SIGTERM}
, socket_{executor} //
{
signals_.async_wait([this](error_code ec, int) {
if (!ec) {
socket_.cancel();
}
});
socket_.open(udp::v4());
socket_.bind({{}, 4444});
receive_loop();
}
private:
asio::signal_set signals_;
udp::socket socket_;
std::array<std::uint8_t, 1024> data_;
udp::endpoint ep_;
void receive_loop() {
socket_.async_receive_from( //
asio::buffer(data_), ep_, [this](error_code ec, size_t) {
if (!ec)
receive_loop();
});
}
};
int main() {
asio::io_context ioc;
Program app(ioc.get_executor());
using namespace std::chrono_literals;
ioc.run_for(10s); // for COLIRU
}
Prints (on coliru):打印(在大肠杆菌上):
@asio|1663593973.457548|0*1|signal_set@0x7ffe0b639998.async_wait
@asio|1663593973.457687|0*2|socket@0x7ffe0b6399f0.async_receive_from
@asio|1663593973.457700|.2|non_blocking_recvfrom,ec=system:11,bytes_transferred=0
@asio|1663593974.467205|.2|non_blocking_recvfrom,ec=system:0,bytes_transferred=13
@asio|1663593974.467252|>2|ec=system:0,bytes_transferred=13
@asio|1663593974.467265|2*3|socket@0x7ffe0b6399f0.async_receive_from
@asio|1663593974.467279|.3|non_blocking_recvfrom,ec=system:11,bytes_transferred=0
@asio|1663593974.467291|<2|
@asio|1663593975.481800|.3|non_blocking_recvfrom,ec=system:0,bytes_transferred=13
@asio|1663593975.481842|>3|ec=system:0,bytes_transferred=13
@asio|1663593975.481854|3*4|socket@0x7ffe0b6399f0.async_receive_from
@asio|1663593975.481868|.4|non_blocking_recvfrom,ec=system:11,bytes_transferred=0
@asio|1663593975.481878|<3|
@asio|1663593976.494097|.4|non_blocking_recvfrom,ec=system:0,bytes_transferred=13
@asio|1663593976.494138|>4|ec=system:0,bytes_transferred=13
@asio|1663593976.494150|4*5|socket@0x7ffe0b6399f0.async_receive_from
@asio|1663593976.494164|.5|non_blocking_recvfrom,ec=system:11,bytes_transferred=0
@asio|1663593976.494176|<4|
@asio|1663593976.495085|>1|ec=system:0,signal_number=2
@asio|1663593976.495119|1|socket@0x7ffe0b6399f0.cancel
@asio|1663593976.495129|<1|
@asio|1663593976.495151|>5|ec=system:125,bytes_transferred=0
@asio|1663593976.495162|<5|
@asio|1663593976.495184|0|socket@0x7ffe0b6399f0.close
@asio|1663593976.495244|0|signal_set@0x7ffe0b639998.cancel
So that's 3 successful receives, followed by a signal 2 (INT) and cancellation which results in ec=125 ( asio::error:operation_aborted
) and shutdown.所以这是 3 次成功接收,然后是信号 2 (INT) 和取消,导致 ec=125 (
asio::error:operation_aborted
) 并关闭。
There's likely no gain for using multiple threads, but if you do, use a strand to synchronize access to the IO objects:使用多线程可能没有任何好处,但如果这样做,请使用链来同步对 IO 对象的访问:
asio::thread_pool ioc;
Program app(make_strand(ioc));
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