Question

我在服务器程序中有奇怪的行为。在简单的例子中它工作正常（我在pion和asio中随处插入痕迹）。

#include <pion/http/server.hpp>
#include <pion/http/response_writer.hpp>
#include <pion/http/response_reader.hpp>
#include <pion/http/request_writer.hpp>
#include <pion/logger.hpp>
#include <pion/scheduler.hpp>

int main()
{
   pion::single_service_scheduler shed;
   shed.set_num_threads(1);
   boost::shared_ptr<pion::http::server> server
   (new pion::http::server(shed, 5000));
   server->add_resource("/", handlerFunction);
   server->start();
   sleep(5);
}

输出是这样的。构造接受器的套接字，为客户端构造套接字，创建tcp连接，一切正常。

basic io object constructor
after service construct
basic io object constructor
after service construct
basic io object constructor
Address of socket is: 0x9855fa4 value: -1
after service construct
1422519945 INFO pion.http.server Added request handler for HTTP resource: 
1422519945 INFO pion.http.server Starting server on port 5000
before connection create
before connection constructor called
basic io object constructor
basic_stream_socket::construct
Address of socket is: 0x9857514 value: -1
after impl.construct
after service construct
basic io object constructor
after service construct
basic io object constructor
after service construct
ssl socket constructed
connection constructor, is_ssl: 0
after connection create: 0x98574f8
before accept
after accept

在更复杂的程序中使用相同的代码，但是使用oracle和许多其他库输出就是这样。

basic io object constructor
after service construct
basic io object constructor
after service construct
basic io object constructor
Address of socket is: 0xbfe47a64 value: -1
after service construct
1422525476 INFO pion.http.server Added request handler for HTTP resource: 
before connection create
basic io object constructor
after service construct
basic io object constructor
after service construct
after connection create: 0x8fe8b88
before accept
in connection::async_accept
after accept

没有创建第二个套接字，实际上，没有connection::create的调用，但是连接有地址，如您所见。我有点想法，某个地方写了函数connection::create的地址（或类似的东西）。你能帮忙吗，我怎么能抓住这个？

Answer 1

在ubuntu上，我喜欢使用valgrind（http://valgrind.org/）投放。

sudo apt-get install valgrind
valgrind ./mypgrogram

它没有报告所有问题，但是当它发生时，它会报告性质和来源。

还建议：

valgrind --db-attach=yes ./myprogram

允许您在检测到违规/未初始化的内存引用时调试（回溯，检查）并继续执行程序。

在一些较旧的Ubunti上，我必须使用sudo使valgrind能够附加gdb：
sudo -E valgrind --db-attach=yes ./myprogram

如果用tr1/unordered_map

替换std::unordered_map应该非常简单

E.g。快速入侵

#include <unordered_map>

namespace std { namespace tr1 {

    using std::unordered_map;
    using std::hash;
    // etc...
} }

当然这不是一个好习惯，你可能只想在std::unordered_map和std::tr1::unordered_map之间输入def，而是为了快速检查......

如何在C ++代码中捕获奇怪的未定义行为？

1 个答案: