linux - C++ Can't link Boost library -

i'm trying compile little piece of code boost documentation: (http://www.boost.org/doc/libs/1_46_1/libs/iostreams/doc/tutorial/filter_usage.html)

#include <boost/iostreams/device/file_descriptor.hpp> #include <boost/iostreams/filtering_stream.hpp>  namespace io = boost::iostreams;  int main() {        io::filtering_ostream out;     out.push(compressor());     out.push(base64_encoder());     out.push(file_sink("my_file.txt"));     // write out using std::ostream interface } 

but refuses compile, following errors:

g++ -c -pipe -g -wall -w -d_reentrant -dqt_gui_lib -dqt_core_lib -dqt_shared -i/usr/share/qt4/mkspecs/linux-g++ -i../teste -i/usr/include/qt4/qtcore -i/usr/include/qt4/qtgui -i/usr/include/qt4 -i. -i../teste -i. -o main.o ../teste/main.cpp

../teste/main.cpp: in function ‘int main()’:

../teste/main.cpp:9:25: error: ‘compressor’ not declared in scope

../teste/main.cpp:10:29: error: ‘base64_encoder’ not declared in scope

../teste/main.cpp:11:37: error: ‘file_sink’ not declared in scope

i know i'm doing stupid can't see what...

edit:

btw, have boost libraries , -dev files installed properly. , i'm using qt-creator, .pro file looks so:

sources += \     main.cpp  libs += \     -lboost_filesystem \     -lboost_iostreams  

i assume refering example at

http://www.boost.org/doc/libs/1_46_1/libs/iostreams/doc/tutorial/filter_usage.html

if read carefully, notice tutorial page states that

if have appropriate outputfilters compressor , base64_encoder, can follows

the code on example page not meant compilable. try example instead:

http://www.boost.org/doc/libs/1_46_1/libs/iostreams/doc/classes/zlib.html#examples

...but sure add using namespace boost::iostreams able compile it, i.e.:

#include <fstream> #include <iostream> #include <boost/iostreams/filtering_streambuf.hpp> #include <boost/iostreams/copy.hpp> #include <boost/iostreams/filter/zlib.hpp>  int main()  {     using namespace std;     using namespace boost::iostreams;      ifstream file("hello.z", ios_base::in | ios_base::binary);     filtering_streambuf<input> in;     in.push(zlib_decompressor());     in.push(file);     boost::iostreams::copy(in, cout); }