【发布时间】：2011-11-25 07:02:52
【问题描述】：
我已经安装了 OpenCV。 我已经能够编译一些代码，但有时它不起作用。下面的例子不起作用。
#include <iostream>
#include "opencv2/opencv.hpp"
#include "opencv2/gpu/gpu.hpp"
int main (int argc, char* argv[])
{
try
{
cv::Mat src_host = cv::imread("building.jpg", CV_LOAD_IMAGE_GRAYSCALE);
cv::gpu::GpuMat dst, src;
src.upload(src_host);
cv::gpu::threshold(src, dst, 128.0, 255.0, CV_THRESH_BINARY);
cv::Mat result_host = dst;
cv::imshow("Result", result_host);
cv::waitKey();
}
catch(const cv::Exception& ex)
{
std::cout << "Error: " << ex.what() << std::endl;
}
return 0;
}
当我使用
编译时出现以下错误gcc Test.cpp $(pkg-config --cflags --libs opencv)
gcc Test.cpp $(pkg-config --cflags --libs opencv)
Undefined symbols for architecture x86_64:
"std::allocator<char>::allocator()", referenced from:
_main in ccnzUIww.o
"std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&)", referenced from:
_main in ccnzUIww.o
"std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()", referenced from:
_main in ccnzUIww.o
"std::terminate()", referenced from:
_main in ccnzUIww.o
"std::allocator<char>::~allocator()", referenced from:
_main in ccnzUIww.o
"cv::gpu::GpuMat::upload(cv::Mat const&)", referenced from:
_main in ccnzUIww.o
"cv::gpu::Stream::Null()", referenced from:
_main in ccnzUIww.o
"cv::gpu::threshold(cv::gpu::GpuMat const&, cv::gpu::GpuMat&, double, double, int, cv::gpu::Stream&)", referenced from:
_main in ccnzUIww.o
"cv::gpu::GpuMat::operator cv::Mat() const", referenced from:
_main in ccnzUIww.o
"___cxa_begin_catch", referenced from:
_main in ccnzUIww.o
"std::cout", referenced from:
_main in ccnzUIww.o
"std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from:
_main in ccnzUIww.o
"std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)", referenced from:
_main in ccnzUIww.o
"std::basic_ostream<char, std::char_traits<char> >::operator<<(std::basic_ostream<char, std::char_traits<char> >& (*)(std::basic_ostream<char, std::char_traits<char> >&))", referenced from:
_main in ccnzUIww.o
"___cxa_end_catch", referenced from:
_main in ccnzUIww.o
"std::ios_base::Init::Init()", referenced from:
__static_initialization_and_destruction_0(int, int)in ccnzUIww.o
"std::ios_base::Init::~Init()", referenced from:
___tcf_0 in ccnzUIww.o
"cv::gpu::GpuMat::release()", referenced from:
cv::gpu::GpuMat::~GpuMat()in ccnzUIww.o
"___gxx_personality_v0", referenced from:
Dwarf Exception Unwind Info (__eh_frame) in ccnzUIww.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
我也试过了：
- gcc Test.cpp $(pkg-config --cflags --libs opencv) -m32
- gcc Test.cpp $(pkg-config --cflags --libs opencv) -m64
- nvcc Test.cpp $(pkg-config --cflags --libs opencv)
但这也会产生错误。我在stackoverflow上寻找答案并找到了这个。 Compiling OpenCV CUDA program 在这个答案中，解决方案是使用这个命令：
g++ Test.cpp `pkg-config --cflags --libs opencv` -lopencv_gpu
而且它有效！我曾尝试为 gcc 和 nvcc 编译器提供相同的参数，但随后又出现错误。这是一个问题，因为我想在 CUDA 项目中使用 OpenCV，所以我必须使用 nvcc 编译器。
我对 C 和 C++ 的经验很少，所以有可能这是显而易见的 :)
【问题讨论】：
-
OpenCV 是 C++，你的示例程序肯定是 C++，不是 C。用 C 编译器编译它没有意义。可以使用 gcc 完成，但它会无缘无故地为您带来大量额外的工作。
-
谢谢！但我需要使用 nvcc 编译器，因为将来我可以在该文件中添加一些 CUDA 代码。
-
使用
nvcc编译，然后g++链接。 -
好的。我想我可以将 CUDA 代码添加到 CUDA 文件，将 C/C++ 代码添加到 C/C++ 文件，然后分别编译和链接它们。