Boost Asio GCC Link Error - c++

Question

I've just installed a clean vm with xubuntu 12.10 and I'm trying to port over some C++ code which works perfectly on Windows. First off, I've installed Virtualbox guest additions and GCC and I can compile code.
I've downloaded the boost library from the internet (boost_1_52) and I've dropped in the asio library from the asio website (boost_asio_1_4_8) and I've installed the multi-threading, shared link version using these instructions:
./bootstrap.sh --prefix=/usr &&
./b2 stage threading=multi link=shared
as root:
I know for a fact that boost works because I've been able to compile the test application here (linking with lboost_regex) and it works perfectly:
#include <boost/regex.hpp>
#include <iostream>
#include <string>
int main()
{
std::string line;
boost::regex pat( "^Subject: (Re: |Aw: )*(.*)" );
while (std::cin)
{
std::getline(std::cin, line);
boost::smatch matches;
if (boost::regex_match(line, matches, pat))
std::cout << matches[2] << std::endl;
}
}
So I'm trying to build one of the ASIO examples, which I've built before with no problems on Windows. The files are here:
http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/examples.html
See:
boost_asio/example/serialization/client.cpp
boost_asio/example/serialization/connection.hpp
boost_asio/example/serialization/server.cpp
boost_asio/example/serialization/stock.hpp
I throw my compiler this:
gcc client.cpp -I /usr/include/boost -lboost_system -lboost_thread -lboost_serialization
Which gives me this error:
connection.hpp:75:35: error: template argument 1 is invalid
connection.hpp:75:35: error: template argument 2 is invalid
connection.hpp:75:44: error: invalid type in declaration before ‘;’ token
connection.hpp:76:13: error: request for member ‘push_back’ in ‘buffers’, which is of non-class type ‘int’
connection.hpp:76:23: error: ‘asio’ is not a class or namespace
connection.hpp:77:13: error: request for member ‘push_back’ in ‘buffers’, which is of non-class type ‘int’
connection.hpp:77:23: error: ‘asio’ is not a class or namespace
connection.hpp:78:5: error: ‘asio’ is not a class or namespace
connection.hpp:78:23: error: ‘socket_’ was not declared in this scope
connection.hpp: In member function ‘void s11n_example::connection::async_read(T&, Handler)’:
connection.hpp:87:15: error: ‘asio’ does not name a type
connection.hpp:87:31: error: expected unqualified-id before ‘&’ token
connection.hpp:87:31: error: expected ‘)’ before ‘&’ token
connection.hpp:87:31: error: expected initializer before ‘&’ token
connection.hpp:90:5: error: ‘asio’ has not been declared
connection.hpp:90:22: error: ‘socket_’ was not declared in this scope
connection.hpp:90:31: error: ‘asio’ has not been declared
connection.hpp:91:21: error: ‘f’ was not declared in this scope
connection.hpp:92:17: error: ‘asio’ has not been declared
client.cpp: At global scope:
client.cpp:26:10: error: ‘asio’ has not been declared
client.cpp:26:26: error: expected ‘)’ before ‘&’ token
client.cpp:43:29: error: ‘asio’ does not name a type
client.cpp:43:45: error: expected unqualified-id before ‘&’ token
client.cpp:43:45: error: expected ‘)’ before ‘&’ token
client.cpp:43:35: error: expected ‘;’ at end of member declaration
client.cpp:43:47: error: ISO C++ forbids declaration of ‘e’ with no type [-fpermissive]
client.cpp:43:47: error: expected ‘;’ at end of member declaration
client.cpp:43:48: error: expected unqualified-id before ‘)’ token
client.cpp:125:1: error: expected ‘}’ at end of input
client.cpp:125:1: error: expected unqualified-id at end of input
client.cpp:125:1: error: expected ‘}’ at end of input
I'm really confused, its as if I've not built boost or I'm missing another link. I've also tried linking with Winsock, with no results. Please help!
Cheers

Answer 1

You are using gcc and g++ interchangeably. The line which doesn't work uses gcc, but the line which works uses g++. Using g++ instead of gcc may effect which default include path is used. Your initial error was not linking. It was compiling. Also, if you use the boost version, asio namespace is not asio. It's boost::asio.

Answer 2

Looks like boost/asio.hpp didn't get included correctly.
I don't remember exactly what the prefix option does, but I think your problem may be somewhere in there. The boost directory may not be in /usr/include/boost, but instead possibly /usr/boost.
That's one possibility. The second is that, instead of passing /usr/include/boost, you need to pass /usr/include, i.e.
gcc client.cpp -I /usr/include -lboost_system -lboost_thread -lboost_serialization
If you look at the example files, e.g. the connection.cpp example, it includes boost/asio.hpp. The boost/ part refers to a folder that should be looked for by the compiler in the include path(s) you specify using -I. So if you specified /usr/include/boost, the compiler is going to look for /usr/include/boost/boost/asio.hpp (notice the 2 occurrences of boost).

Answer 3

I think I've fixed the problem now. Using bjam and the auto-installer doesn't seem to accomplish much (it won't resolve to those paths for some reason).
Anyway, I downloaded the ASIO source code (non-boost this time) and put that in a directory on my desktop. In a similar fashion to how I do it on windows in Visual Studio, I managed to get it to link:
g++ client.cpp -I/home/devbox/desktop/asio-1.5.3/include - L/home/devbox/Desktop/boost_1_53_0/stage/lib -lboost_system -lboost_thread -lboost_serialization -o test
Cheers all