在 C++ 项目中包含 dlib 库时出错答案

【问题标题】：Error including dlib library in c++ project在 C++ 项目中包含 dlib 库时出错
【发布时间】：2016-09-09 14:08:44
【问题描述】：

我需要在 c++ 项目中包含 dlib。我已在我的 Makefile 中正确链接了该库。这是 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/

我不知道为什么，但它在编译时出错。我也编译了 dlib 库本身，并且代码示例正在运行。我得到的错误是：

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

我无法弄清楚我在将库链接到项目时做了什么。请帮忙。

【问题讨论】：

联动命令在哪里？
请在您的 dlib 库和 exe 上运行 ldd -r 并确保没有报告未定义的符号
假设您的 exe 名为 <some path>/my_exe。您需要运行ldd -r <some path>/my_exe 并查看没有错误报告。如果您看到错误，则必须将缺少的库添加到链接行和/或缺少的路径到 LD_LIBRARY_PATH 或其类似物。
我没有可执行文件，因为代码中有错误。所以我真的不能按照你的建议去做。
对你的dlib 库执行此操作，因为我似乎问题在于该库的链接？

标签： c++ makefile dlib

【解决方案1】：

Dlib 部分基于标头，某些函数需要将 libdlib.a 链接到项目您有两种方法可以解决您的问题：

链接到 dlib：LDFLAGS = -ldlib（应安装 dlib 或其路径提供给链接器）
将 dlib/all/source.cpp 添加到您的项目源列表 (CXXFILES)

【讨论】：

在做第一件事时，它无法识别 -ldlib。在第二点，错误是：src/source.cpp:7:41: fatal error: ../base64/base64_kernel_1.cpp: No such file or directory #include "../base64/base64_kernel_1.cpp"跨度>
您不应将 source.cpp 复制到您的项目中，而应提供完整的绝对路径
现在错误是：/usr/bin/ld: /tmp/ccps6CPH.o: undefined reference to symbol 'pthread_create@@GLIBC_2.2.5' //lib/x86_64-linux-gnu/libpthread .so.0：添加符号时出错：命令行collect2中缺少DSO：错误：ld返回1退出状态make：*** [face_frontalization]错误1
我该如何安装 Dlib？我只找到了如何使用 cmake 编译它。
cmake --build 。 --目标安装

【解决方案2】：

如果在使用 dLib 编译期间出现此错误：

/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

X11 丢失的可能性很大。我不知道它是什么所以如果有人这样做，请告诉我。解决方案是将-lX11 添加到LDFLAGS 以便与之链接。如果你不想要它，你也可以指定编译器选项-DDLIB_NO_GUI_SUPPORT。

（注意：我没有测试过它，也不知道 X11 做了什么，所以包含它比排除它更好。）

【讨论】：