Boost web client error (newbee)
Hi,
I'm a newbee of C++. I want to make a web client with boost libraries.
I have ubuntu (libboost1.46-dev) and I follow the example that appear
in boost web page:
#include <iostream>
#include <istream>
#include <ostream>
#include <string>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
using boost::asio::ip::tcp;
class client
{
public:
client(boost::asio::io_service& io_service,
const std::string& server, const std::string& path)
: resolver_(io_service),
socket_(io_service)
{
// Form the request. We specify the "Connection: close" header so
that the
// server will close the socket after transmitting the response.
This will
// allow us to treat all data up until the EOF as the content.
std::ostream request_stream(&request_);
request_stream << "GET " << path << " HTTP/1.0\r\n";
request_stream << "Host: " << server << "\r\n";
request_stream << "Accept: */*\r\n";
request_stream << "Connection: close\r\n\r\n";
// Start an asynchronous resolve to translate the server and
service names
// into a list of endpoints.
tcp::resolver::query query(server, "http");
resolver_.async_resolve(query,
boost::bind(&client::handle_resolve, this,
boost::asio::placeholders::error,
boost::asio::placeholders::iterator));
}
private:
void handle_resolve(const boost::system::error_code& err,
tcp::resolver::iterator endpoint_iterator)
{
if (!err)
{
// Attempt a connection to the first endpoint in the list. Each
endpoint
// will be tried until we successfully establish a connection.
tcp::endpoint endpoint = *endpoint_iterator;
socket_.async_connect(endpoint,
boost::bind(&client::handle_connect, this,
boost::asio::placeholders::error, ++endpoint_iterator));
}
else
{
std::cout << "Error: " << err.message() << "\n";
}
}
void handle_connect(const boost::system::error_code& err,
tcp::resolver::iterator endpoint_iterator)
{
if (!err)
{
// The connection was successful. Send the request.
boost::asio::async_write(socket_, request_,
boost::bind(&client::handle_write_request, this,
boost::asio::placeholders::error));
}
else if (endpoint_iterator != tcp::resolver::iterator())
{
// The connection failed. Try the next endpoint in the list.
socket_.close();
tcp::endpoint endpoint = *endpoint_iterator;
socket_.async_connect(endpoint,
boost::bind(&client::handle_connect, this,
boost::asio::placeholders::error, ++endpoint_iterator));
}
else
{
std::cout << "Error: " << err.message() << "\n";
}
}
void handle_write_request(const boost::system::error_code& err)
{
if (!err)
{
// Read the response status line. The response_ streambuf will
// automatically grow to accommodate the entire line. The growth
may be
// limited by passing a maximum size to the streambuf
constructor.
boost::asio::async_read_until(socket_, response_, "\r\n",
boost::bind(&client::handle_read_status_line, this,
boost::asio::placeholders::error));
}
else
{
std::cout << "Error: " << err.message() << "\n";
}
}
void handle_read_status_line(const boost::system::error_code& err)
{
if (!err)
{
// Check that response is OK.
std::istream response_stream(&response_);
std::string http_version;
response_stream >> http_version;
unsigned int status_code;
response_stream >> status_code;
std::string status_message;
std::getline(response_stream, status_message);
if (!response_stream || http_version.substr(0, 5) != "HTTP/")
{
std::cout << "Invalid response\n";
return;
}
if (status_code != 200)
{
std::cout << "Response returned with status code ";
std::cout << status_code << "\n";
return;
}
// Read the response headers, which are terminated by a blank
line.
boost::asio::async_read_until(socket_, response_, "\r\n\r\n",
boost::bind(&client::handle_read_headers, this,
boost::asio::placeholders::error));
}
else
{
std::cout << "Error: " << err << "\n";
}
}
void handle_read_headers(const boost::system::error_code& err)
{
if (!err)
{
// Process the response headers.
std::istream response_stream(&response_);
std::string header;
while (std::getline(response_stream, header) && header != "\r")
std::cout << header << "\n";
std::cout << "\n";
// Write whatever content we already have to output.
if (response_.size() > 0)
std::cout << &response_;
// Start reading remaining data until EOF.
boost::asio::async_read(socket_, response_,
boost::asio::transfer_at_least(1),
boost::bind(&client::handle_read_content, this,
boost::asio::placeholders::error));
}
else
{
std::cout << "Error: " << err << "\n";
}
}
void handle_read_content(const boost::system::error_code& err)
{
if (!err)
{
// Write all of the data that has been read so far.
std::cout << &response_;
// Continue reading remaining data until EOF.
boost::asio::async_read(socket_, response_,
boost::asio::transfer_at_least(1),
boost::bind(&client::handle_read_content, this,
boost::asio::placeholders::error));
}
else if (err != boost::asio::error::eof)
{
std::cout << "Error: " << err << "\n";
}
}
tcp::resolver resolver_;
tcp::socket socket_;
boost::asio::streambuf request_;
boost::asio::streambuf response_;
};
int main(int argc, char* argv[])
{
try
{
if (argc != 3)
{
std::cout << "Usage: async_client <server> <path>\n";
std::cout << "Example:\n";
std::cout << " async_client www.boost.org /LICENSE_1_0.txt\n";
return 1;
}
boost::asio::io_service io_service;
client c(io_service, argv[1], argv[2]);
io_service.run();
}
catch (std::exception& e)
{
std::cout << "Exception: " << e.what() << "\n";
}
return 0;
}
but I receive these errors:
/tmp/cc-u4FMYi.o: In function `__cxx_global_var_init1':
b.cpp:(.text+0x57): undefined reference to
`boost::system::generic_category()'
/tmp/cc-u4FMYi.o: In function `__cxx_global_var_init2':
b.cpp:(.text+0x77): undefined reference to
`boost::system::generic_category()'
/tmp/cc-u4FMYi.o: In function `__cxx_global_var_init3':
b.cpp:(.text+0x97): undefined reference to
`boost::system::system_category()'
/tmp/cc-u4FMYi.o: In function
`boost::asio::error::get_system_category()':
b.cpp:
(.text._ZN5boost4asio5error19get_system_categoryEv[_ZN5boost4asio5error19get_system_categoryEv]
+0x7): undefined reference to `boost::system::system_category()'
/tmp/cc-u4FMYi.o: In function
`boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::strand_service::strand_impl>::context>::~posix_tss_ptr()':
b.cpp:
(.text._ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_14strand_service11strand_implEE7contextEED2Ev[_ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_14strand_service11strand_implEE7contextEED2Ev]
+0x18): undefined reference to `pthread_key_delete'
/tmp/cc-u4FMYi.o: In function
`boost::asio::detail::posix_tss_ptr_create(unsigned int&)':
b.cpp:
(.text._ZN5boost4asio6detail20posix_tss_ptr_createERj[_ZN5boost4asio6detail20posix_tss_ptr_createERj]
+0x33): undefined reference to `pthread_key_create'
/tmp/cc-u4FMYi.o: In function
`boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service>::context>::~posix_tss_ptr()':
b.cpp:
(.text._ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceEE7contextEED2Ev[_ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceEE7contextEED2Ev]
+0x18): undefined reference to `pthread_key_delete'
/tmp/cc-u4FMYi.o: In function
`boost::system::error_code::error_code()':
b.cpp:
(.text._ZN5boost6system10error_codeC2Ev[_ZN5boost6system10error_codeC2Ev]
+0x19): undefined reference to `boost::system::system_category()'
/tmp/cc-u4FMYi.o: In function
`boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service>::context>::operator=(boost::asio::detail::call_stack<boost::asio::detail::task_io_service>::context*)':
b.cpp:
(.text._ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceEE7contextEEaSEPS6_[_ZN5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceEE7contextEEaSEPS6_]
+0x22): undefined reference to `pthread_setspecific'
/tmp/cc-u4FMYi.o: In function
`boost::asio::detail::posix_tss_ptr<boost::asio::detail::call_stack<boost::asio::detail::task_io_service>::context>::operator
boost::asio::detail::call_stack<boost::asio::detail::task_io_service>::context*()
const':
b.cpp:
(.text._ZNK5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceEE7contextEEcvPS6_Ev[_ZNK5boost4asio6detail13posix_tss_ptrINS1_10call_stackINS1_15task_io_serviceEE7contextEEcvPS6_Ev]
+0x15): undefined reference to `pthread_getspecific'
/tmp/cc-u4FMYi.o: In function
`boost::asio::detail::posix_thread::start_thread(boost::asio::detail::posix_thread::func_base*)':
b.cpp:
(.text._ZN5boost4asio6detail12posix_thread12start_threadEPNS2_9func_baseE[_ZN5boost4asio6detail12posix_thread12start_threadEPNS2_9func_baseE]
+0x3b): undefined reference to `pthread_create'
/tmp/cc-u4FMYi.o: In function
`boost::asio::detail::posix_thread::~posix_thread()':
b.cpp:
(.text._ZN5boost4asio6detail12posix_threadD2Ev[_ZN5boost4asio6detail12posix_threadD2Ev]
+0x2c): undefined reference to `pthread_detach'
/tmp/cc-u4FMYi.o: In function
`boost::asio::detail::posix_thread::join()':
b.cpp:
(.text._ZN5boost4asio6detail12posix_thread4joinEv[_ZN5boost4asio6detail12posix_thread4joinEv]
+0x3c): undefined reference to `pthread_join'
clang: error: linker command failed with exit code 1 (use -v to see
invocation)
What can I do?
This bunch of errors overpasses me ;-)
Thanks in advance,
Xan.