Compiler error with yaml-cpp - undefined reference to `YAML::detail::node_data::convert_to_map`

Question

Here's the complete log:

/tmp/ccCvErNZ.o: In function `YAML::detail::node& YAML::detail::node_data::get<std::string>(std::string const&, std::shared_ptr<YAML::detail::memory_holder>)':
cricket.cpp:(.text._ZN4YAML6detail9node_data3getISsEERNS0_4nodeERKT_St10shared_ptrINS0_13memory_holderEE[_ZN4YAML6detail9node_data3getISsEERNS0_4nodeERKT_St10shared_ptrINS0_13memory_holderEE]+0x94): undefined reference to `YAML::detail::node_data::convert_to_map(std::shared_ptr<YAML::detail::memory_holder>)'
collect2: error: ld returned 1 exit status

The code I'm trying to compile is simple

#include <iostream>
#include <yaml-cpp/yaml.h>

using namespace std;

int main() {
    YAML::Node test = YAML::LoadFile("test.yaml");
    if (test["date"]) {
      cout << "HELLO";
    }

    return 0;
}

The YAML I'm using is the example from http://www.yaml.org/start.html

If I just try to load the YAML, it loads fine. But if I try to access any data I get the same error. So it's not a linking problem.

EDIT: I can do things like cout << test and cout << test.type() and other functions. I think the problem is in using a string based map for accessing internal nodes.

Answer 1

It seems that you are not properly linking the yaml-cpp library. Add the argument -lyaml-cpp when compiling. For example:

g++ -I/usr/local/include -L/usr/local/lib -lyaml-cpp -o test main.cpp

---

EDIT

Another option is to include this cmake to your CMakeLists.txt:

# attempt to find static library first if this is set
if(YAMLCPP_STATIC_LIBRARY)
    set(YAMLCPP_STATIC libyaml-cpp.a)
endif()

# find the yaml-cpp include directory
find_path(YAMLCPP_INCLUDE_DIR yaml-cpp/yaml.h
          PATH_SUFFIXES include
          PATHS
          ~/Library/Frameworks/yaml-cpp/include/
          /Library/Frameworks/yaml-cpp/include/
          /usr/local/include/
          /usr/include/
          /sw/yaml-cpp/         # Fink
          /opt/local/yaml-cpp/  # DarwinPorts
          /opt/csw/yaml-cpp/    # Blastwave
          /opt/yaml-cpp/
          ${YAMLCPP_DIR}/include/)

# find the yaml-cpp library
find_library(YAMLCPP_LIBRARY
             NAMES ${YAMLCPP_STATIC} yaml-cpp
             PATH_SUFFIXES lib64 lib
             PATHS ~/Library/Frameworks
                    /Library/Frameworks
                    /usr/local
                    /usr
                    /sw
                    /opt/local
                    /opt/csw
                    /opt
                    ${YAMLCPP_DIR}/lib)

# handle the QUIETLY and REQUIRED arguments and set YAMLCPP_FOUND to TRUE if all listed variables are TRUE
include(FindPackageHandleStandardArgs)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(YAMLCPP DEFAULT_MSG YAMLCPP_INCLUDE_DIR YAMLCPP_LIBRARY)
mark_as_advanced(YAMLCPP_INCLUDE_DIR YAMLCPP_LIBRARY)