Question

I keep running across errors when trying to compile code which utilizes the boost::filesystem library. I don’t understand any of the compiler outputs I am getting. Here is my code copied from http://www.highscore.de/cpp/boost/dateisystem.html#dateisystem_pfadangaben:

#include <boost/filesystem.hpp>
#include <iostream>

int main(){
  boost::filesystem::path p("C:\\Windows\\System");
  std::cout << p.root_name() << std::endl; 
  std::cout << p.root_directory() << std::endl; 
  std::cout << p.root_path() << std::endl; 
  std::cout << p.relative_path() << std::endl; 
  std::cout << p.parent_path() << std::endl; 
  std::cout << p.filename() << std::endl; 
} 

I have Ubuntu 11.10 and I have installed libbost-dev and g++. This is what the terminal looks like:

sam@sam-MT6707:~/Dokumente/Programming/Projekte/FTP-abgleicher$ g++ -o pr3 pr3.cpp
/tmp/ccrN7yHl.o: In function `main':
pr3.cpp:(.text+0x3b): undefined reference to `boost::filesystem3::path::root_name() const'
pr3.cpp:(.text+0x7e): undefined reference to `boost::filesystem3::path::root_directory() const'
pr3.cpp:(.text+0xc1): undefined reference to `boost::filesystem3::path::root_path() const'
pr3.cpp:(.text+0x104): undefined reference to `boost::filesystem3::path::relative_path() const'
pr3.cpp:(.text+0x147): undefined reference to `boost::filesystem3::path::parent_path() const'
pr3.cpp:(.text+0x18a): undefined reference to `boost::filesystem3::path::filename() const'
pr3.cpp:(.text+0x1e8): undefined reference to `boost::filesystem3::path::stem() const'
pr3.cpp:(.text+0x22b): undefined reference to `boost::filesystem3::path::extension() const'

/tmp/ccrN7yHl.o: In function `__static_initialization_and_destruction_0(int, int)':
pr3.cpp:(.text+0x364): undefined reference to `boost::system::generic_category()'
pr3.cpp:(.text+0x36e): undefined reference to `boost::system::generic_category()'
pr3.cpp:(.text+0x378): undefined reference to `boost::system::system_category()'
/tmp/ccrN7yHl.o: In function `boost::filesystem3::path::codecvt()':
pr3.cpp:(.text._ZN5boost11filesystem34path7codecvtEv[boost::filesystem3::path::codecvt()]+0x7): undefined reference to `boost::filesystem3::path::wchar_t_codecvt_facet()'
collect2: ld gab 1 als Ende-Status zurück

^Translation of last line: ld returned an end status of 1

What am I doing wrong?

Answer 1

You have to link with -lboost_filesystem -lboost_system. Boost filesystem is not a header-only library; rather, it depends on compiled components.