尝试构建 C++ Dlib 示例失败 link，出现数百个未定义的引用错误

Question

我正在尝试编译一个 DLIB 示例：http://dlib.net/image_ex.cpp.html 然后我逐字复制：

#include <dlib/gui_widgets.h>
#include <dlib/image_io.h>
#include <dlib/image_transforms.h>
#include <fstream>


using namespace std;
using namespace dlib;

//  ----------------------------------------------------------------------------

int main(int argc, char** argv)
{
    try
    {
        // make sure the user entered an argument to this program
        if (argc != 2)
        {
            cout << "error, you have to enter a BMP file as an argument to this program" << endl;
            return 1;
        }

我使用了这个命令：

g++ dlib1.cpp -o dlib1 -std=c++11 -O3 -I ~/Packages/dlib/ -lpthread -lX11 -ljpeg -lpng -DDLIB_JPEG_SUPPORT -DDLIB_PNG_SUPPORT

尽管几个月前该命令运行良好：[] 这次，它给了我数百个错误：

dlibTest-0.cpp:(.text._ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_[_ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_]+0x7e): undefined reference to `dlib::png_loader::is_gray() const'
dlibTest-0.cpp:(.text._ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_[_ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_]+0x94): undefined reference to `dlib::png_loader::is_gray() const'
dlibTest-0.cpp:(.text._ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_[_ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_]+0xaa): undefined reference to `dlib::png_loader::is_graya() const'
dlibTest-0.cpp:(.text._ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_[_ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_]+0xd0): undefined reference to `dlib::png_loader::get_row(unsigned int) const'
dlibTest-0.cpp:(.text._ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_[_ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_]+0x176): undefined reference to `dlib::png_loader::get_row(unsigned int) const'
dlibTest-0.cpp:(.text._ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_[_ZNK4dlib10png_loader9get_imageINS_7array2dINS_9rgb_pixelENS_33memory_manager_stateless_kernel_1IcEEEEEEvRT_]+0x1ce): undefined reference to `dlib::png_loader::is_graya() const'

这里到底出了什么问题？

Answer 1

一些示例需要命令行，例如...

g++ -std=c++11 -O3 -I.. ../dlib/all/source.cpp -lpthread -lX11 example_program_name.cpp

我猜source.cpp是一个"library as cpp code"link : dlib compile

尝试构建 C++ Dlib 示例失败 link，出现数百个未定义的引用错误

Trying to build C++ Dlib example fails to link with hundreds of undefined reference errors

c++

linker-errors

dlib