I want to use jsoncpp for writing a C++ code in order to parse a JSON file. Let me explain what I did. I created a CMakeLists.txt and I made a FindJsoncpp.cmake along with a simple c++ file to test jsoncpp. When I compile the C++ source without cmake using -I/usr/include/jsoncpp/ -ljsoncpp it works fine. but when I try to build it using cmake it cannot find json.h header file that I included in my c++ source code.
here is my CMakeLists.txt:
cmake_minimum_required (VERSION 2.6) project (Parser) set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/Modules/") include(LibFindMacros) message("----------- trying to find Jsoncpp-------------") find_package(Jsoncpp) if(Jsoncpp_FOUND) message("INFO: we found LibJsoncpp on your pc.") message(Jsoncpp_FOUND = ${Jsoncpp_FOUND}) message(Jsoncpp_INCLUDE_DIR = ${Jsoncpp_INCLUDE_DIR}) message(Jsoncpp_LIBRARY = ${Jsoncpp_LIBRARY}) else(Jsoncpp_FOUND) message("WARNING: we couldn't find LibJsoncpp on your pc. DLC is disabled.") endif(Jsoncpp_FOUND) #set(LIBS ${Jsoncpp_LIBRARY}) # Set the include dir variables and the libraries and let libfind_process do the rest. # NOTE: Singular variables for this library, plural for libraries this this lib depends on. set(Jsoncpp_PROCESS_INCLUDES Jsoncpp_INCLUDE_DIR) set(Jsoncpp_PROCESS_LIBS Jsoncpp_LIBRARY) # add the executable add_executable(jsonparser jsonparser.cpp) And this is the FindJsoncpp.cmake that I wrote:
# - Try to find Jsoncpp # Once done, this will define # # Jsoncpp_FOUND - system has Jsoncpp # Jsoncpp_INCLUDE_DIRS - the Jsoncpp include directories # Jsoncpp_LIBRARIES - link these to use Jsoncpp include(LibFindMacros) # Use pkg-config to get hints about paths libfind_pkg_check_modules(Jsoncpp_PKGCONF jsoncpp) # Include dir find_path(Jsoncpp_INCLUDE_DIR NAMES json/json.h # PATHS ./jsoncpp/ PATHS ${Jsoncpp_PKGCONF_INCLUDE_DIRS} # /usr/include/jsoncpp/json ) # Finally the library itself find_library(Jsoncpp_LIBRARY NAMES jsoncpp PATHS ${Jsoncpp_PKGCONF_LIBRARY_DIRS} # PATH ./jsoncpp/ ) set(Jsoncpp_PROCESS_INCLUDES Jsoncpp_INCLUDE_DIR) set(Jsoncpp_PROCESS_LIBS Jsoncpp_LIBRARY) libfind_process(Jsoncpp) And finally a simple C++ code called jsonparser.cpp to test it:
#include <iostream> #include <fstream> #include <json/json.h> using namespace std; void printSongInfo(Json::Value song){ std::clog<<"\n-----------printing a song-------------\n"; std::clog<<"Name="<<song["name"]; std::clog<<"Artist="<<song["artist"]; } int main(){ std::ifstream catalogFile("catalog.json"); Json::Value root; // will contains the root value after parsing. Json::Reader reader; bool parsingSuccessful = reader.parse( catalogFile, root ); if ( !parsingSuccessful ){ // report to the user the failure and their locations in the document. std::cout << "Failed to parse configuration\n" << reader.getFormattedErrorMessages(); return 1; } //parsing songs const Json::Value songs = root["songs"]; for ( int index = 0; index < songs.size(); ++index ){ // Iterates over the sequence elements. printSongInfo(songs[index] ); } return 0; } When I run the jsonparser.cpp with below command it works just fine.
g++ -I/usr/include/jsoncpp/ -ljsoncpp jsonparser.cpp but when I try to make it using cmake I get this error:
$~/jsoncppTest/build$ cmake .. -- The C compiler identification is GNU 4.7.3 -- The CXX compiler identification is GNU 4.7.3 -- Check for working C compiler: /usr/bin/cc -- Check for working C compiler: /usr/bin/cc -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Check for working CXX compiler: /usr/bin/c++ -- Check for working CXX compiler: /usr/bin/c++ -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done ----------- trying to find Jsoncpp------------- -- Found PkgConfig: /usr/bin/pkg-config (found version "0.26") -- checking for module 'jsoncpp' -- found jsoncpp, version 0.6.0 -- Found Jsoncpp INFO: we found LibJsoncpp on your pc. Jsoncpp_FOUND=TRUE Jsoncpp_INCLUDE_DIR=/usr/include/jsoncpp Jsoncpp_LIBRARY=/usr/lib/libjsoncpp.so -- Configuring done -- Generating done -- Build files have been written to: ~/jsoncppTest/build $~/jsoncppTest/build$ make Scanning dependencies of target jsonparser [100%] Building CXX object CMakeFiles/jsonparser.dir/jsonparser.cpp.o ~/jsoncppTest/jsonparser.cpp:3:23: fatal error: json/json.h: No such file or directory compilation terminated. make[2]: *** [CMakeFiles/jsonparser.dir/jsonparser.cpp.o] Error 1 make[1]: *** [CMakeFiles/jsonparser.dir/all] Error 2 make: *** [all] Error 2 It cannot find json/json.h header file but it has founded the jsoncpp library in cmake before. I checked jsoncpp.pc file and found ti OK. I don't know what I am doing wrong! any help would be appreciated.
I am using ubuntu 13.04 with multiarch support. I heard something about jsoncpp problem with 64bit compiler but don't know if that's the case.