Opencv linking libraries - Undefined Reference - c++

I tried to compile opencv codes on raspberry pi 3.However, it gives always "undefined reference ... " error, i think there is a problem with linking.
Compile:
g++ `pkg-config --libs --cflags opencv` Face_Detection.cpp
pkg-config opencv --libs:
-L/opt/lib/ -L/opt/Deneme/opencv/a/ -opencv_calib3d -opencv_core
-opencv_features2d -opencv_flann -opencv_highgui -opencv_imgcodecs
-opencv_imgproc -opencv_ml -opencv_objdetect -opencv_photo -opencv_shape
-opencv_stitching -opencv_superres -opencv_videoio -opencv_video
-opencv_calib3d_pch_dephelp -opencv_contrib_pch_dephelp
-opencv_core_pch_dephelp -opencv_features2d_pch_dephelp
-opencv_flann_pch_dephelp -opencv_gpu_pch_dephelp
-opencv_haartraining_engine -opencv_highgui_pch_dephelp
-opencv_imgproc_pch_dephelp -opencv_legacy_pch_dephelp
-opencv_ml_pch_dephelp -opencv_objdetect_pch_dephelp
-opencv_video_pch_dephelp
pkg-config opencv --cflags:
-I/opt/Deneme/Include/opencv -I/opt/Deneme/Include/
opencv.pc file:
includedir=/opt/Deneme/Include/opencv
dir2=/opt/Deneme/Include/
libdir=/opt/lib/
libdir2=/opt/Deneme/opencv/a/
Name: opencv
Description: The opencv library
Version: 3.x.x
Cflags: -I${includedir} -I${dir2}
Libs: -L${libdir} -opencv_calib3d -opencv_core -opencv_features2d - opencv_flann -opencv_highgui -opencv_imgcodecs -opencv_imgproc -opencv_ml -opencv_objdetect -opencv_photo -opencv_shape -opencv_stitching -opencv_superres -opencv_videoio -opencv_video -L${libdir2} -opencv_calib3d_pch_dephelp -opencv_contrib_pch_dephelp -opencv_core_pch_dephelp -opencv_features2d_pch_dephelp -opencv_flann_pch_dephelp -opencv_gpu_pch_dephelp -opencv_haartraining_engine -opencv_highgui_pch_dephelp -opencv_imgproc_pch_dephelp -opencv_legacy_pch_dephelp -opencv_ml_pch_dephelp -opencv_objdetect_pch_dephelp -opencv_video_pch_dephelp
error:
Face_Detection.cpp:(.text+0x94): undefined reference to `cv::imread(std::string const&, int)'
Face_Detection.cpp:(.text+0xd8): undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
Face_Detection.cpp:(.text+0xec): undefined reference to `cv::_OutputArray::_OutputArray(cv::Mat&)'
Face_Detection.cpp:(.text+0x128): undefined reference to `cv::resize(cv::_InputArray const&, cv::_OutputArray const&, cv::Size_<int>, double, double, int)'
Face_Detection.cpp:(.text+0x1e8): undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
Face_Detection.cpp:(.text+0x218): undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
Face_Detection.cpp:(.text+0x250): undefined reference to `cv::_OutputArray::_OutputArray(cv::Mat&)'
Face_Detection.cpp:(.text+0x26c): undefined reference to `cv::hconcat(cv::_InputArray const&, cv::_InputArray const&, cv::_OutputArray const&)'
Face_Detection.cpp:(.text+0x298): undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
Face_Detection.cpp:(.text+0x2c8): undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
Thanks in advance.

It was linker order error. Try to change
g++ `pkg-config --libs --cflags opencv` Face_Detection.cpp
to
g++ Face_Detection.cpp `pkg-config --libs --cflags opencv`

Related

Undefined reference errors for OpenCV Hello World in Ubuntu

I'm trying the following code:
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>
using namespace cv;
int main(int argc, char** argv) {
namedWindow("Output",1);
Mat output = Mat::zeros( 120, 350, CV_8UC3 );
putText(output,"Hello World",cvPoint(15,70),
FONT_HERSHEY_PLAIN,3,cvScalar(0,255,0),4);
imshow("Output", output);
waitKey(0);
return 0;
}
I then tried g++ -I/usr/local/include -L/usr/local/lib -lopencv_core -lopencv_imgcodecs -lopencv_highgui opencv_hello.cpp -o opencv_hello
and g++pkg-config opencv cvblob --cflags --libsopencv_hello.cpp -o opencv_hello
But they both give the same undefined reference errors:
opencv_hello.cpp:(.text+0x132): undefined reference to `cv::namedWindow(cv::String const&, int)'
opencv_hello.cpp:(.text+0x15f): undefined reference to `cv::Mat::zeros(int, int, int)'
opencv_hello.cpp:(.text+0x26f): undefined reference to `cv::putText(cv::_InputOutputArray const&, cv::String const&, cv::Point_<int>, int, double, cv::Scalar_<double>, int, int, bool)'
opencv_hello.cpp:(.text+0x2d7): undefined reference to `cv::imshow(cv::String const&, cv::_InputArray const&)'
opencv_hello.cpp:(.text+0x2ff): undefined reference to `cv::waitKey(int)'
/tmp/cctt8VGQ.o: In function `cv::String::String(char const*)':
opencv_hello.cpp:(.text._ZN2cv6StringC2EPKc[_ZN2cv6StringC5EPKc]+0x4d): undefined reference to `cv::String::allocate(unsigned long)'
/tmp/cctt8VGQ.o: In function `cv::String::~String()':
opencv_hello.cpp:(.text._ZN2cv6StringD2Ev[_ZN2cv6StringD5Ev]+0x14): undefined reference to `cv::String::deallocate()'
/tmp/cctt8VGQ.o: In function `cv::Mat::~Mat()':
opencv_hello.cpp:(.text._ZN2cv3MatD2Ev[_ZN2cv3MatD5Ev]+0x39): undefined reference to `cv::fastFree(void*)'
/tmp/cctt8VGQ.o: In function `cv::Mat::release()':
opencv_hello.cpp:(.text._ZN2cv3Mat7releaseEv[_ZN2cv3Mat7releaseEv]+0x4b): undefined reference to `cv::Mat::deallocate()'
How can I fix this?
If pkg-config opencv --cflags --libs command finds OpenCV include files and libraries below compilation works wituout any errors.
g++ opencv_hello.cpp -o opencv_hello $(pkg-config opencv --cflags --libs)
or
g++ opencv_hello.cpp -o opencv_hello `pkg-config opencv --cflags --libs`

C++ Boost: undefined reference to boost::system::generic_category() in Windows

I am trying to compile this code in CodeBlocks
#include <boost/filesystem.hpp>
#include <iostream>
using namespace boost::filesystem;
int main()
{
if ( !boost::filesystem::exists( "myfile.txt" ) )
{
std::cout << "Can't find my file!" << std::endl;
}
}
With this compile flags:
g++.exe -Wall -fexceptions -g -O3 -pedantic-errors -Wall -std=c++0x -lboost_system -IC:\Users\moe\Desktop\boost_1_67_0 -c C:\Users\moe\Desktop\oo\main.cpp -o obj\Debug\main.o
But I always receive this error:
boost::system::generic_category()
this is the error log, that i receive when i compile the code:
Untitled4.o: In function `boost::system::error_category::std_category::equivalent(std::error_code const&, int) const':
C:/Users/moe/Desktop/boost_1_67_0/boost/system/error_code.hpp:733: undefined reference to `boost::system::generic_category()'
C:/Users/moe/Desktop/boost_1_67_0/boost/system/error_code.hpp:736: undefined reference to `boost::system::generic_category()'
C:/Users/moe/Desktop/boost_1_67_0/boost/system/error_code.hpp:748: undefined reference to `boost::system::generic_category()'
Untitled4.o: In function `boost::system::error_category::std_category::equivalent(int, std::error_condition const&) const':
C:/Users/moe/Desktop/boost_1_67_0/boost/system/error_code.hpp:703: undefined reference to `boost::system::generic_category()'
C:/Users/moe/Desktop/boost_1_67_0/boost/system/error_code.hpp:706: undefined reference to `boost::system::generic_category()'
Untitled4.o: In function `boost::filesystem::path_traits::convert(char const*, char const*, std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >&)':
C:/Users/moe/Desktop/boost_1_67_0/boost/filesystem/path.hpp:981: undefined reference to `boost::filesystem::path::codecvt()'
C:/Users/moe/Desktop/boost_1_67_0/boost/filesystem/path.hpp:981: undefined reference to `boost::filesystem::path_traits::convert(char const*, char const*, std::__cxx11::basic_string<wchar_t, std::char_traits<wchar_t>, std::allocator<wchar_t> >&, std::codecvt<wchar_t, char, int> const&)'
Untitled4.o: In function `boost::filesystem::exists(boost::filesystem::path const&)':
C:/Users/moe/Desktop/boost_1_67_0/boost/filesystem/operations.hpp:446: undefined reference to `boost::filesystem::detail::status(boost::filesystem::path const&, boost::system::error_code*)'
collect2.exe: error: ld returned 1 exit status
Put the libraries at the end of the linker command line:
Why does the order of '-l' option in gcc matter?
Since your erro log also contained these:
C:/Users/moe/Desktop/boost_1_67_0/boost/filesystem/path.hpp:981: undefined reference to `boost::filesystem::path::codecvt()'
It is clear that you also lack -lboost_filesystem.
So there is no use to just add -lboost_system to the g++ command.
You can add -lboost_system -lboost_filesystem to your g++ command.

Error including dlib library in c++ project

I need to include dlib in a c++ project. I have properly linked the library in my Makefile. Here is the Makefile:
EXE = face_frontalization
OBJ_DIR = bin
CFLAGS = -g -w
# CXXFLAGS = -w -Wall -Wextra -g -std=c++0x
# LDFLAGS = -lSDL2 -lSDL2_image -lSDL2_ttf -lSDL2_mixer -lSDL2_gfx -lm
dummy_build_folder := $(shell mkdir -p $(OBJ_DIR))
# c++ source files of the project
CXXFILES = $(shell find src -type f -name '*.cpp')
CXXOBJ = $(patsubst src/%.cpp,bin/%.o,$(CXXFILES))
INCLUDE = -I/usr/include/dlib-18.18
LIBS = `pkg-config --libs opencv`
CXXFLAGS = `pkg-config --cflags opencv` -w -Wall -Wextra -g -std=c++0x
LDFLAGS = -lcurl
CFLAGS = `pkg-config --cflags opencv` -g -w
MKDIR = mkdir -p
ifdef V
MUTE =
VTAG = -v
else
MUTE = #
endif
###################################################################
# This is a Makefile progress indicator.
# BUILD is initially undefined
ifndef BUILD
# max equals 256 x's
sixteen := x x x x x x x x x x x x x x x x
MAX := $(foreach x,$(sixteen),$(sixteen))
# T estimates how many targets we are building by replacing BUILD with
# a special string
T := $(shell $(MAKE) -nrRf $(firstword $(MAKEFILE_LIST)) $(MAKECMDGOALS) \
BUILD="COUNTTHIS" | grep -c "COUNTTHIS")
# N is the number of pending targets in base 1, well in fact, base x
# :-)
N := $(wordlist 1,$T,$(MAX))
# auto-decrementing counter that returns the number of pending targets
# in base 10
counter = $(words $N)$(eval N := $(wordlist 2,$(words $N),$N))
# BUILD is now defined to show the progress, this also avoids
# redefining T in loop
BUILD = #echo $(counter) of $(T)
endif
###################################################################
# .PHONY: directories all
#
# directories: ${OUT_DIR}
# ${OUT_DIR}:
# ${MKDIR} ${OUT_DIR}
all: $(EXE)
# build successful
$(EXE): $(CXXOBJ)
$(CXX) $(CXXOBJ) -o $(EXE) $(LIBS) $(LDFLAGS)
$(OBJ_DIR)/%.o: src/%.cpp
$(CXX) $(CXXFLAGS) $(INCLUDE) $< -c -o $#
$(BUILD)
$(OBJ_DIR)/%.o: src/%.c
$(CC) $(CFLAGS) $(INCLUDE) $< -c -o $#
run: all
./$(EXE)
clean:
# Cleaning...
-rm -f $(EXE) $(CXXOBJ)
rmdir bin/
I dont know why but its giving errors on compilation. I have compiled the dlib library itself too and the code examples are running as they should.
The error I am getting is:
bin/fatialfeaturedetect.o: In function `fatial_feature_detector()':
/home/playroom/Desktop/face-frontalization/src/fatialfeaturedetect.cpp:20: undefined reference to `dlib::base_window::wait_until_closed() const'
/home/playroom/Desktop/face-frontalization/src/fatialfeaturedetect.cpp:18: undefined reference to `dlib::image_window::~image_window()'
/home/playroom/Desktop/face-frontalization/src/fatialfeaturedetect.cpp:18: undefined reference to `dlib::image_window::~image_window()'
bin/fatialfeaturedetect.o: In function `dlib::get_serialized_frontal_faces()':
/usr/include/dlib-18.18/dlib/image_processing/frontal_face_detector.h:115: undefined reference to `dlib::base64::base64()'
/usr/include/dlib-18.18/dlib/image_processing/frontal_face_detector.h:2358: undefined reference to `dlib::base64::decode(std::istream&, std::ostream&) const'
/usr/include/dlib-18.18/dlib/image_processing/frontal_face_detector.h:2367: undefined reference to `dlib::base64::~base64()'
/usr/include/dlib-18.18/dlib/image_processing/frontal_face_detector.h:2367: undefined reference to `dlib::base64::~base64()'
bin/fatialfeaturedetect.o: In function `dlib_check_consistent_assert_usage':
/usr/include/dlib-18.18/dlib/gui_widgets/../gui_core/../threads/threads_kernel_shared.h:44: undefined reference to `USER_ERROR__missing_dlib_all_source_cpp_file__OR__inconsistent_use_of_DEBUG_or_ENABLE_ASSERTS_preprocessor_directives_'
bin/fatialfeaturedetect.o: In function `dlib::drawable_window::drawable_window(bool, bool)':
/usr/include/dlib-18.18/dlib/gui_widgets/drawable.h:79: undefined reference to `dlib::base_window::base_window(bool, bool)'
/usr/include/dlib-18.18/dlib/gui_widgets/drawable.h:79: undefined reference to `vtable for dlib::drawable_window'
/usr/include/dlib-18.18/dlib/gui_widgets/drawable.h:79: undefined reference to `dlib::base_window::~base_window()'
bin/fatialfeaturedetect.o: In function `dlib::drawable_window::~drawable_window()':
/usr/include/dlib-18.18/dlib/gui_widgets/drawable.h:195: undefined reference to `vtable for dlib::drawable_window'
/usr/include/dlib-18.18/dlib/gui_widgets/drawable.h:195: undefined reference to `dlib::base_window::close_window()'
/usr/include/dlib-18.18/dlib/gui_widgets/drawable.h:195: undefined reference to `dlib::base_window::~base_window()'
bin/fatialfeaturedetect.o: In function `dlib::scrollable_region_style_default::draw_scrollable_region_border(dlib::canvas const&, dlib::rectangle const&, bool) const':
/usr/include/dlib-18.18/dlib/gui_widgets/style.h:527: undefined reference to `dlib::draw_sunken_rectangle(dlib::canvas const&, dlib::rectangle const&, unsigned char)'
bin/fatialfeaturedetect.o: In function `dlib::image_display::disable_overlay_editing()':
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3485: undefined reference to `dlib::base_window::invalidate_rectangle(dlib::rectangle const&)'
bin/fatialfeaturedetect.o: In function `dlib::compress_stream_kernel_1<dlib::entropy_encoder_model_kernel_5<257ul, dlib::entropy_encoder_kernel_2, 200000ul, 4ul>, dlib::entropy_decoder_model_kernel_5<257ul, dlib::entropy_decoder_kernel_2, 200000ul, 4ul>, dlib::crc32>::decompress(std::istream&, std::ostream&) const':
/usr/include/dlib-18.18/dlib/image_processing/../compress_stream/compress_stream_kernel_1.h:180: undefined reference to `dlib::entropy_decoder_kernel_2::entropy_decoder_kernel_2()'
/usr/include/dlib-18.18/dlib/image_processing/../compress_stream/compress_stream_kernel_1.h:181: undefined reference to `dlib::entropy_decoder_kernel_2::set_stream(std::istream&)'
/usr/include/dlib-18.18/dlib/image_processing/../compress_stream/compress_stream_kernel_1.h:196: undefined reference to `dlib::entropy_decoder_kernel_2::get_target(unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../compress_stream/compress_stream_kernel_1.h:201: undefined reference to `dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../compress_stream/compress_stream_kernel_1.h:243: undefined reference to `dlib::entropy_decoder_kernel_2::~entropy_decoder_kernel_2()'
/usr/include/dlib-18.18/dlib/image_processing/../compress_stream/compress_stream_kernel_1.h:243: undefined reference to `dlib::entropy_decoder_kernel_2::~entropy_decoder_kernel_2()'
bin/fatialfeaturedetect.o: In function `void dlib::image_window::add_overlay<dlib::rgb_pixel>(std::vector<dlib::rectangle, std::allocator<dlib::rectangle> > const&, dlib::rgb_pixel)':
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3968: undefined reference to `dlib::image_window::add_overlay(std::vector<dlib::image_display::overlay_rect, std::allocator<dlib::image_display::overlay_rect> > const&)'
bin/fatialfeaturedetect.o: In function `dlib::image_window::image_window<dlib::array2d<dlib::rgb_pixel, dlib::memory_manager_stateless_kernel_1<char> > >(dlib::array2d<dlib::rgb_pixel, dlib::memory_manager_stateless_kernel_1<char> > const&)':
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3883: undefined reference to `vtable for dlib::image_window'
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3883: undefined reference to `dlib::image_display::image_display(dlib::drawable_window&)'
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3885: undefined reference to `dlib::image_window::on_image_clicked(dlib::vector<long, 2l> const&, bool, unsigned long)'
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3888: undefined reference to `dlib::base_window::show()'
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3883: undefined reference to `dlib::image_display::~image_display()'
bin/fatialfeaturedetect.o: In function `dlib::entropy_decoder_model_kernel_5<257ul, dlib::entropy_decoder_kernel_2, 200000ul, 4ul>::decode(unsigned long&)':
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_5.h:422: undefined reference to `dlib::entropy_decoder_kernel_2::get_target(unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_5.h:456: undefined reference to `dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_5.h:503: undefined reference to `dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_5.h:551: undefined reference to `dlib::entropy_decoder_kernel_2::get_target(unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_5.h:553: undefined reference to `dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
bin/fatialfeaturedetect.o: In function `void dlib::image_window::set_image<dlib::array2d<dlib::rgb_pixel, dlib::memory_manager_stateless_kernel_1<char> > >(dlib::array2d<dlib::rgb_pixel, dlib::memory_manager_stateless_kernel_1<char> > const&)':
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3930: undefined reference to `dlib::image_display::get_image_display_rect() const'
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3934: undefined reference to `dlib::base_window::set_size(int, int)'
bin/fatialfeaturedetect.o: In function `void dlib::load_dng<dlib::array2d<dlib::rgb_pixel, dlib::memory_manager_stateless_kernel_1<char> > >(dlib::array2d<dlib::rgb_pixel, dlib::memory_manager_stateless_kernel_1<char> >&, std::istream&)':
/usr/include/dlib-18.18/dlib/image_loader/image_loader.h:585: undefined reference to `dlib::entropy_decoder_kernel_2::entropy_decoder_kernel_2()'
/usr/include/dlib-18.18/dlib/image_loader/image_loader.h:586: undefined reference to `dlib::entropy_decoder_kernel_2::set_stream(std::istream&)'
/usr/include/dlib-18.18/dlib/image_loader/image_loader.h:757: undefined reference to `dlib::entropy_decoder_kernel_2::~entropy_decoder_kernel_2()'
/usr/include/dlib-18.18/dlib/image_loader/image_loader.h:771: undefined reference to `dlib::entropy_decoder_kernel_2::entropy_decoder_kernel_2()'
/usr/include/dlib-18.18/dlib/image_loader/image_loader.h:772: undefined reference to `dlib::entropy_decoder_kernel_2::set_stream(std::istream&)'
/usr/include/dlib-18.18/dlib/image_loader/image_loader.h:771: undefined reference to `dlib::entropy_decoder_kernel_2::~entropy_decoder_kernel_2()'
/usr/include/dlib-18.18/dlib/image_loader/image_loader.h:757: undefined reference to `dlib::entropy_decoder_kernel_2::~entropy_decoder_kernel_2()'
/usr/include/dlib-18.18/dlib/image_loader/image_loader.h:771: undefined reference to `dlib::entropy_decoder_kernel_2::~entropy_decoder_kernel_2()'
bin/fatialfeaturedetect.o: In function `void dlib::image_display::set_image<dlib::array2d<dlib::rgb_pixel, dlib::memory_manager_stateless_kernel_1<char> > >(dlib::array2d<dlib::rgb_pixel, dlib::memory_manager_stateless_kernel_1<char> > const&)':
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3272: undefined reference to `dlib::scrollable_region::set_total_rect_size(unsigned long, unsigned long)'
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3274: undefined reference to `dlib::scrollable_region::set_total_rect_size(unsigned long, unsigned long)'
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3278: undefined reference to `dlib::base_window::invalidate_rectangle(dlib::rectangle const&)'
/usr/include/dlib-18.18/dlib/gui_widgets/widgets.h:3283: undefined reference to `dlib::popup_menu_region::disable()'
bin/fatialfeaturedetect.o: In function `dlib::entropy_decoder_model_kernel_5<256ul, dlib::entropy_decoder_kernel_2, 200000ul, 4ul>::decode(unsigned long&)':
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_5.h:422: undefined reference to `dlib::entropy_decoder_kernel_2::get_target(unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_5.h:456: undefined reference to `dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_5.h:503: undefined reference to `dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_5.h:551: undefined reference to `dlib::entropy_decoder_kernel_2::get_target(unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_5.h:553: undefined reference to `dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
bin/fatialfeaturedetect.o: In function `dlib::entropy_decoder_model_kernel_4<256ul, dlib::entropy_decoder_kernel_2, 200000ul, 4ul>::decode(unsigned long&)':
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_4.h:348: undefined reference to `dlib::entropy_decoder_kernel_2::get_target(unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_4.h:376: undefined reference to `dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_4.h:422: undefined reference to `dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_4.h:469: undefined reference to `dlib::entropy_decoder_kernel_2::get_target(unsigned int)'
/usr/include/dlib-18.18/dlib/image_processing/../entropy_decoder_model/entropy_decoder_model_kernel_4.h:471: undefined reference to `dlib::entropy_decoder_kernel_2::decode(unsigned int, unsigned int)'
collect2: error: ld returned 1 exit status
make: *** [face_frontalization] Error 1
I cant figure out what I have done in linking the library to the project. Please help.
Dlib is partially header-based and some functions need to have libdlib.a linked to a project
You have two ways how to solve your problem:
link to dlib: LDFLAGS = -ldlib (dlib should be installed or its path provided to linker)
add dlib/all/source.cpp to your project sources list(CXXFILES)
If this error is present during compilation with dLib:
/usr/bin/ld: /tmp/ccps6CPH.o: undefined reference to symbol 'pthread_create##GLIBC_2.2.5'
//lib/x86_64-linux-gnu/libpthread.so.0: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status make: *** [face_frontalization] Error 1
There is a good probability that X11 is missing. I dont know what it is so if somebody does, please tell me. Solution is to just add -lX11 to the LDFLAGS in order to link with it. If you dont want it, you can also specify compiler option -DDLIB_NO_GUI_SUPPORT.
(NOTE: I haven't tested it and dont know what X11 does so better include it than exclude it.)

Error when linking with libmongoclient in c++

When I start compiling the code with clang, it seems like libmongoclient doesn't exist. However, I compile the legacy version of mongo-cxx-client on this ubuntu machine. This code is working correctly on my Mac.
clang -lstdc++ -stdlib=libc++ -lcurl -lpthread -ljsoncpp -lboost_system -lboost_regex -lmongoclient -L/usr/lib main.o qqlogin.o fetcher.o -o qq_crawler
this is the code for linking. It didn't make any difference with or without the parameter -lmongoclient. I have already make sure it is under the correct path and the compile are able to search it.
main.o: In function `main':
main.cpp:(.text+0x3b): undefined reference to `mongo::client::Options::Options()'
main.cpp:(.text+0x4b): undefined reference to `mongo::client::GlobalInstance::GlobalInstance(mongo::client::Options const&)'
main.cpp:(.text+0x2d4): undefined reference to `mongo::client::GlobalInstance::~GlobalInstance()'
main.cpp:(.text+0x310): undefined reference to `mongo::client::GlobalInstance::~GlobalInstance()'
main.o: In function `thread_main(threadtool::Threadsafe_queue<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >*)':
main.cpp:(.text+0x343): undefined reference to `mongo::DBClientConnection::DBClientConnection(bool, mongo::DBClientReplicaSet*, double)'
main.o: In function `GCC_except_table14':
main.cpp:(.gcc_except_table+0x258): undefined reference to `typeinfo for mongo::DBException'
main.o: In function `mongo::DBClientConnection::connect(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)':
main.cpp:(.text._ZN5mongo18DBClientConnection7connectERKNSt3__112basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEE[_ZN5mongo18DBClientConnection7connectERKNSt3__112basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEE]+0x116): undefined reference to `mongo::HostAndPort::HostAndPort(mongo::StringData const&)'
main.o: In function `mongo::DBClientConnection::~DBClientConnection()':
main.cpp:(.text._ZN5mongo18DBClientConnectionD2Ev[_ZN5mongo18DBClientConnectionD2Ev]+0x12): undefined reference to `vtable for mongo::DBClientConnection'
main.cpp:(.text._ZN5mongo18DBClientConnectionD2Ev[_ZN5mongo18DBClientConnectionD2Ev]+0x1d): undefined reference to `vtable for mongo::DBClientConnection'
main.cpp:(.text._ZN5mongo18DBClientConnectionD2Ev[_ZN5mongo18DBClientConnectionD2Ev]+0x22): undefined reference to `mongo::DBClientConnection::_numConnections'
main.cpp:(.text._ZN5mongo18DBClientConnectionD2Ev[_ZN5mongo18DBClientConnectionD2Ev]+0xc4): undefined reference to `mongo::DBClientBase::~DBClientBase()'
main.cpp:(.text._ZN5mongo18DBClientConnectionD2Ev[_ZN5mongo18DBClientConnectionD2Ev]+0x15d): undefined reference to `mongo::DBClientBase::~DBClientBase()'
main.o: In function `mongo::DBException::~DBException()':
main.cpp:(.text._ZN5mongo11DBExceptionD2Ev[_ZN5mongo11DBExceptionD2Ev]+0xc): undefined reference to `vtable for mongo::DBException'
main.o: In function `mongo::UserException::UserException(int, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)':
main.cpp:(.text._ZN5mongo13UserExceptionC2EiRKNSt3__112basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEE[_ZN5mongo13UserExceptionC2EiRKNSt3__112basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEE]+0x30): undefined reference to `vtable for mongo::UserException'
main.o: In function `mongo::DBException::addContext(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)':
main.cpp:(.text._ZN5mongo11DBException10addContextERKNSt3__112basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEE[_ZN5mongo11DBException10addContextERKNSt3__112basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEE]+0x51): undefined reference to `mongo::causedBy(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)'
main.o: In function `mongo::DBException::DBException(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, int)':
main.cpp:(.text._ZN5mongo11DBExceptionC2ERKNSt3__112basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEEi[_ZN5mongo11DBExceptionC2ERKNSt3__112basic_stringIcNS1_11char_traitsIcEENS1_9allocatorIcEEEEi]+0xf): undefined reference to `vtable for mongo::DBException'
main.o:(.rodata._ZTIN5mongo16ConnectExceptionE[_ZTIN5mongo16ConnectExceptionE]+0x10): undefined reference to `typeinfo for mongo::UserException'
main.o:(.rodata._ZTVN5mongo16ConnectExceptionE[_ZTVN5mongo16ConnectExceptionE]+0x30): undefined reference to `mongo::UserException::appendPrefix(std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char> >&) const'
main.o:(.rodata._ZTVN5mongo16ConnectExceptionE[_ZTVN5mongo16ConnectExceptionE]+0x40): undefined reference to `mongo::DBException::toString() const'
main.o:(.rodata._ZTVN5mongo18AssertionExceptionE[_ZTVN5mongo18AssertionExceptionE]+0x40): undefined reference to `mongo::DBException::toString() const'
main.o:(.rodata._ZTIN5mongo18AssertionExceptionE[_ZTIN5mongo18AssertionExceptionE]+0x10): undefined reference to `typeinfo for mongo::DBException'
fetcher.o: In function `fetch::Fetcher::parsed_json(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&)':
fetcher.cpp:(.text+0x1e8c): undefined reference to `Json::Reader::parse(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, Json::Value&, bool)'
fetcher.o: In function `mongo::BSONObjBuilder::BSONObjBuilder(int)':
fetcher.cpp:(.text._ZN5mongo14BSONObjBuilderC2Ei[_ZN5mongo14BSONObjBuilderC2Ei]+0x4e): undefined reference to `mongo::BSONObjBuilderValueStream::BSONObjBuilderValueStream(mongo::BSONObjBuilder*)'
fetcher.o: In function `mongo::BSONObjBuilder::append(mongo::StringData const&, mongo::Date_t)':
fetcher.cpp:(.text._ZN5mongo14BSONObjBuilder6appendERKNS_10StringDataENS_6Date_tE[_ZN5mongo14BSONObjBuilder6appendERKNS_10StringDataENS_6Date_tE]+0x29): undefined reference to `mongo::BSONObjBuilder::appendDate(mongo::StringData const&, mongo::Date_t)'
fetcher.o: In function `mongo::BSONObjBuilder::obj()':
fetcher.cpp:(.text._ZN5mongo14BSONObjBuilder3objEv[_ZN5mongo14BSONObjBuilder3objEv]+0x4c): undefined reference to `mongo::msgasserted(int, char const*)'
fetcher.o: In function `mongo::BSONObjBuilder::_done()':
fetcher.cpp:(.text._ZN5mongo14BSONObjBuilder5_doneEv[_ZN5mongo14BSONObjBuilder5_doneEv]+0x62): undefined reference to `mongo::BSONObjBuilderValueStream::endField(mongo::StringData const&)'
fetcher.o: In function `mongo::_BufBuilder<mongo::TrivialAllocator>::claimReservedBytes(int)':
fetcher.cpp:(.text._ZN5mongo11_BufBuilderINS_16TrivialAllocatorEE18claimReservedBytesEi[_ZN5mongo11_BufBuilderINS_16TrivialAllocatorEE18claimReservedBytesEi]+0x52): undefined reference to `mongo::invariantFailed(char const*, char const*, unsigned int)'
fetcher.o: In function `mongo::_BufBuilder<mongo::TrivialAllocator>::grow_reallocate(int)':
fetcher.cpp:(.text._ZN5mongo11_BufBuilderINS_16TrivialAllocatorEE15grow_reallocateEi[_ZN5mongo11_BufBuilderINS_16TrivialAllocatorEE15grow_reallocateEi]+0x663): undefined reference to `mongo::msgasserted(int, char const*)'
fetcher.cpp:(.text._ZN5mongo11_BufBuilderINS_16TrivialAllocatorEE15grow_reallocateEi[_ZN5mongo11_BufBuilderINS_16TrivialAllocatorEE15grow_reallocateEi]+0x6ed): undefined reference to `mongo::msgasserted(int, char const*)'
fetcher.o: In function `mongo::checkFieldName(mongo::StringData)':
fetcher.cpp:(.text._ZN5mongo14checkFieldNameENS_10StringDataE[_ZN5mongo14checkFieldNameENS_10StringDataE]+0x56): undefined reference to `mongo::uasserted(int, char const*)'
fetcher.o: In function `mongo::_BufBuilder<mongo::TrivialAllocator>::_BufBuilder(int)':
fetcher.cpp:(.text._ZN5mongo11_BufBuilderINS_16TrivialAllocatorEEC2Ei[_ZN5mongo11_BufBuilderINS_16TrivialAllocatorEEC2Ei]+0x5e): undefined reference to `mongo::msgasserted(int, char const*)'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [qq_crawler] Error 1
Put your object files before the libraries:
clang -stdlib=libc++ main.o qqlogin.o fetcher.o -L/usr/lib -lcurl -lpthread
-ljsoncpp -lboost_system -lboost_regex -lmongoclient -o qq_crawler

error using already compiled version of openCV

I've used the already compiled version of openCV for Raspberry Pi. link for anyone who is interested
After trying to compile using this command line
g++ test3.cpp -o test3 -I/usr/local/include/ -lraspicam -lraspicam_cv -L/opt/vc/lib -lmmal -lmmal_core -lmmal_util -I/usr/include -lopencv_core -lopencv_highgui -lopencv_imgproc -lwiringPi -lpthread
I get the following error lines.
//usr/local/lib/libopencv_stitching.so.2.4: undefined reference to `cv::gpu::ensureSizeIsEnough(int, int, int, cv::gpu::GpuMat&)'
//usr/local/lib/libopencv_calib3d.so.2.4: undefined reference to `cv::parallel_for_(cv::Range const&, cv::ParallelLoopBody const&, double)'
//usr/local/lib/libopencv_calib3d.so.2.4: undefined reference to `typeinfo for cv::ParallelLoopBody'
//usr/local/lib/libopencv_calib3d.so.2.4: undefined reference to `cv::Mutex::unlock()'
//usr/local/lib/libopencv_calib3d.so.2.4: undefined reference to `cv::Mutex::lock()'
//usr/local/lib/libopencv_ocl.so.2.4: undefined reference to cv::TLSDataContainer::getData() const
//usr/local/lib/libopencv_features2d.so.2.4: undefined reference to cv::AlgorithmInfo::addParam(cv::Algorithm&, char const*, unsigned char&, bool, unsigned char (cv::Algorithm::)(), void (cv::Algorithm::)(unsigned char), std::basic_string, std::allocator > const&)
//usr/local/lib/libopencv_features2d.so.2.4: undefined reference to `cv::AlgorithmInfo::addParam(cv::Algorithm&, char const*, float&, bool, float (cv::Algorithm::)(), void (cv::Algorithm::)(float), std::basic_string, std::allocator > const&)'
//usr/local/lib/libopencv_features2d.so.2.4: undefined reference to `cv::AlgorithmInfo::addParam(cv::Algorithm&, char const*, short&, bool, int (cv::Algorithm::)(), void (cv::Algorithm::)(int), std::basic_string, std::allocator > const&)'
//usr/local/lib/libopencv_calib3d.so.2.4: undefined reference to `cv::Mutex::Mutex()'
//usr/local/lib/libopencv_ocl.so.2.4: undefined reference to `cv::TLSDataContainer::TLSDataContainer()'
//usr/local/lib/libopencv_calib3d.so.2.4: undefined reference to `cv::ParallelLoopBody::~ParallelLoopBody()'
//usr/local/lib/libopencv_calib3d.so.2.4: undefined reference to `cv::Mutex::~Mutex()'
//usr/local/lib/libopencv_ocl.so.2.4: undefined reference to `cv::TLSDataContainer::~TLSDataContainer()'
collect2: ld returned 1 exit status
You have not linked the executable against several libraries that are required by the program
Try using this:
g++ -lpthread `pkg-config opencv --libs` -I/usr/local/include/ -lraspicam -lraspicam_cv -L/opt/vc/lib -lmmal -lmmal_core -lmmal_util -I/usr/include -lwiringPi test3.cpp -o test3