C++ boost asio异步编译错误

Question

我正在编译这个简单的boost :: asio异步服务器，它的失败与这个错误，任何想法？

#include <iostream> 
#include <boost/asio.hpp> 
#include <boost/bind.hpp> 
#include <boost/thread.hpp> 
#include <boost/shared_ptr.hpp> 
#include <boost/enable_shared_from_this.hpp> 

using namespace std; 


using namespace boost::asio; 
using namespace boost::posix_time; 
typedef boost::shared_ptr<ip::tcp::socket> socket_ptr; 

int main() 
{ 

    io_service service; 
    void start_accept(socket_ptr sock); 
    void handle_accept(socket_ptr sock, const boost::system::error_code & err); 
    ip::tcp::endpoint ep(ip::tcp::v4(), 2001); 
    ip::tcp::acceptor acc(service, ep); 
    socket_ptr sock(new ip::tcp::socket(service)); 
    start_accept(sock); 
    service.run(); 

} 

void start_accept(socket_ptr sock) 
{ 
    acc.async_accept(*sock, boost::bind(handle_accept, sock, _1)); 
} 


void handle_accept(socket_ptr sock, const boost::system::error_code & err) 
{ 
    if (err) return; 
    socket_ptr sock(new ip::tcp::socket(service)); 
    start_accept(sock); 
} 

错误： 编写本

[root@kris server]# g++ -o test3 test3.cpp -lboost_system -lpthread -lboost_thread-mt 
test3.cpp: In function ‘void start_accept(socket_ptr)’: 
test3.cpp:31: error: ‘acc’ was not declared in this scope 
test3.cpp:31: error: ‘handle_accept’ was not declared in this scope 
test3.cpp: In function ‘void handle_accept(socket_ptr, const boost::system::error_code&)’: 
test3.cpp:38: error: declaration of ‘socket_ptr sock’ shadows a parameter 
test3.cpp:38: error: ‘service’ was not declared in this scope 

错误编译FREDS版本：

#include <iostream> 
#include <boost/asio.hpp> 
#include <boost/bind.hpp> 
#include <boost/thread.hpp> 
#include <boost/shared_ptr.hpp> 
#include <boost/enable_shared_from_this.hpp> 

using namespace std; 


using namespace boost::asio; 
using namespace boost::posix_time; 
typedef boost::shared_ptr<ip::tcp::socket> socket_ptr; 

class myAcceptor 
{ 
    io_service service; 
    ip::tcp::endpoint ep(ip::tcp::v4(), 2001); 
    ip::tcp::acceptor acc(service, ep); 
    socket_ptr sock(new ip::tcp::socket(service)); 

    myAcceptor(): ep(ip::tcp::v4(), 2001),acc(service,ep), 
    sock(new ip::tcp::socket(service)) 
    { start_accept(); } 

    void run() 
    { 
     service.run(); 
    } 

    void start_accept() 
    { 
     acc.async_accept(boost::bind(handle_accept, _1)); 
    } 

    void handle_accept(const boost::system::error_code & err) 
    { 
     if (err) return; 
     sock = socket_ptr(new ip::tcp::socket(service)); 
     start_accept(sock); 
    } 
}; 
int main() 
{ 
    myAcceptor acceptIt; 
    acceptIt.run(); 
} 



g++ -o test4 test4.cpp -lboost_system -lpthread -lboost_thread-mt 


test4.cpp:18: error: ‘boost::asio::ip::tcp::v4’ is not a type 
test4.cpp:18: error: expected identifier before numeric constant 
test4.cpp:18: error: expected ‘,’ or ‘...’ before numeric constant 
test4.cpp:19: error: ‘service’ is not a type 
test4.cpp:19: error: ‘ep’ is not a type 
test4.cpp:20: error: expected identifier before ‘new’ 
test4.cpp:20: error: expected ‘,’ or ‘...’ before ‘new’ 
test4.cpp: In constructor ‘myAcceptor::myAcceptor()’: 
test4.cpp:22: error: class ‘myAcceptor’ does not have any field named ‘ep’ 
test4.cpp:22: error: class ‘myAcceptor’ does not have any field named ‘acc’ 
test4.cpp:23: error: class ‘myAcceptor’ does not have any field named ‘sock’ 
test4.cpp: In member function ‘void myAcceptor::start_accept()’: 
test4.cpp:33: error: ‘((myAcceptor*)this)->myAcceptor::acc’ does not have class type 
test4.cpp:33: error: no matching function for call to ‘bind(<unresolved overloaded function type>, boost::arg<1>&)’ 
/usr/include/boost/bind/bind.hpp:1461: note: candidates are: boost::_bi::bind_t<boost::_bi::unspecified, F, typename boost::_bi::list_av_1<A1>::type> boost::bind(F, A1) [with F = void (myAcceptor::*)(const boost::system::error_code&), A1 = boost::arg<1>] 
/usr/include/boost/bind/bind.hpp:1710: note:     boost::_bi::bind_t<typename boost::_bi::dm_result<M T::*, A1>::type, boost::_mfi::dm<M, T>, typename boost::_bi::list_av_1<A1>::type> boost::bind(M T::*, A1) [with A1 = boost::arg<1>, M = void(const boost::system::error_code&), T = myAcceptor] 
test4.cpp: In member function ‘void myAcceptor::handle_accept(const boost::system::error_code&)’: 
test4.cpp:39: error: invalid use of member (did you forget the ‘&’ ?) 
test4.cpp:40: error: no matching function for call to ‘myAcceptor::start_accept(<unresolved overloaded function type>)’ 
test4.cpp:31: note: candidates are: void myAcceptor::start_accept() 
test4.cpp: In function ‘int main()’: 
test4.cpp:22: error: ‘myAcceptor::myAcceptor()’ is private 
test4.cpp:45: error: within this context 
test4.cpp:26: error: ‘void myAcceptor::run()’ is private 
test4.cpp:46: error: within this context 

Answer 1

的acc变量仅在main范围。 您需要将其设为全局变量 - 定义类中的所有内容。

class myAcceptor 
{ 
    io_service service; 
    ip::tcp::endpoint ep; 
    ip::tcp::acceptor acc; 
    socket_ptr sock; 

    myAcceptor(): ep(ip::tcp::v4(), 2001),acc(service,ep), 
    sock(new ip::tcp::socket(service)) 
    { start_accept(); } 

    void run() 
    { 
    service.run(); 
    } 

    void start_accept() 
    { 
    acc.async_accept(boost::bind(handle_accept, _1)); 
    } 

    void handle_accept(const boost::system::error_code & err) 
    { 
    if (err) return; 
    sock = socket_ptr(new ip::tcp::socket(service)); 
    start_accept(sock); 
    } 
}; 

int main() 
{ 
    myAcceptor acceptIt; 
    acceptIt.run(); 
} 

Answer 2

让acc全球（不建议报告），或者将它传递给函数：

void start_accept(socket_ptr sock, ip::tcp::acceptor &acc) 
{ 
    acc.async_accept(*sock, boost::bind(handle_accept, sock, _1)); 
} 

Answer 3

test3.cpp:31: error: ‘acc’ was not declared in this scope

什么弗雷德里克和MM。说。

test3.cpp:31: error: ‘handle_accept’ was not declared in this scope

由于start_accept depends上handle_accept，反之亦然，你将不得不转发申报一个。在您的代码中，转发start_accept之前声明handle_accept。

test3.cpp:38: error: declaration of ‘socket_ptr sock’ shadows a parameter 
test3.cpp:38: error: ‘service’ was not declared in this scope 

也许你只是想在传递sock参数start_accept？虽然这个函数看起来很没意思。

另外，我不得不说，如果不能阅读这些非常基本的编译错误，你将会在asio和通用版本中遇到困难。