关于Makefile无法找到库 [英] About Makefile can't find libraries

问题描述

异常在这里：

  g ++ -L / usr / local / lib -I ./include -I。 -lopencv_core -lopencv_highgui -lopencv_imgproc main.o ColorTransfer.o 
 main.o：在函数showImg（std :: string，cv :: Mat，int）中：
 main.cpp :( .text + 0x21）：对`cv :: namedWindow（std :: string const&，int）'的未定义引用
 main.cpp :( .text + 0x34）：未定义对`cv :: _ InputArray :: _ InputArray cv :: Mat const&）'
 main.cpp :(。text + 0x75）：对`cv :: imshow（std :: string const& ;,; cv :: _ InputArray const&）的未定义引用'
 main.cpp :(。text + 0x9d）：对`cv :: waitKey（int）'的未定义引用
 main.o：在函数`main'中：
  

Makefile 在这里：

  CC = g ++ 
 FLAGS = -L。/ lib -I./include -I。 -lopencv_core -lopencv_highgui -lopencv_imgproc 
 
全部：ColorTransfer 
 
 ColorTransfer：main.o ColorTransfer.o 
 $（CC）$（FLAGS）main.o ColorTransfer。 o -o ColorTransfer 
 
 main.o：main.cpp 
 $（CC）$（FLAGS）-c main.cpp -o main.o 
 
 ColorTransfer .o：ColorTransfer.cpp ColorTransfer.h 
 $（CC）$（FLAGS）-c ColorTransfer.cpp -o ColorTransfer.o 
 
 clean：
 rm -rf main。 o ColorTransfer.o 
  

当前目录包含名为lib的目录，其中包含opencv库。

解决方案

您真的应该注意 g ++ ;它很重要（图书馆应该保持良好状态 - 从最高级到最低级）。

使用 make -p 以了解 make ....的规则，然后改进您的 Makefile ，如下所示

  CXX = g ++ 
 CXXFLAGS = -I./include -I。 -g -Wall 
 LDLIBS = -L./lib -lopencv_core -lopencv_highgui -lopencv_imgproc 
 
 all：ColorTransfer 
 
 ColorTransfer：main.o ColorTransfer.o 
 $（LINK.cc）$ ^ $（LDLIBS）-o $ @ 
 
＃etc ... 
  

我让你纠正你的 Makefile 的其他行...参见

^{我更正了上面的制作规则： $ ^ 必须位于 $（LDLIBS）！}

顺便说一句，重拍是一个很好的工具来调试 Makefile -s;例如，用 remake -x

The Exception is here:

g++ -L/usr/local/lib -I./include -I. -lopencv_core -lopencv_highgui -lopencv_imgproc main.o ColorTransfer.o
main.o: In function `showImg(std::string, cv::Mat, int)':
main.cpp:(.text+0x21): undefined reference to `cv::namedWindow(std::string const&, int)'
main.cpp:(.text+0x34): undefined reference to `cv::_InputArray::_InputArray(cv::Mat const&)'
main.cpp:(.text+0x75): undefined reference to `cv::imshow(std::string const&, cv::_InputArray const&)'
main.cpp:(.text+0x9d): undefined reference to `cv::waitKey(int)'
main.o: In function `main':

And the Makefile is here:

CC=g++
FLAGS=-L./lib -I./include -I. -lopencv_core -lopencv_highgui -lopencv_imgproc

all: ColorTransfer

ColorTransfer: main.o ColorTransfer.o
    $(CC) $(FLAGS) main.o ColorTransfer.o -o ColorTransfer

main.o: main.cpp 
    $(CC) $(FLAGS) -c main.cpp -o main.o

ColorTransfer.o: ColorTransfer.cpp ColorTransfer.h
    $(CC) $(FLAGS) -c ColorTransfer.cpp -o ColorTransfer.o

clean :
    rm -rf main.o ColorTransfer.o

And current directory contains directory named lib, which has opencv libraries.

解决方案

You really should pay attention to the order of arguments to g++ ; it matters a lot (libraries should go last in good order - highest level to lowest level).

Use  make -p to learn about rules known to make.... Then improve your Makefile as follow

 CXX=g++
 CXXFLAGS= -I./include -I. -g -Wall
 LDLIBS= -L./lib -lopencv_core -lopencv_highgui -lopencv_imgproc

 all: ColorTransfer

 ColorTransfer: main.o ColorTransfer.o
           $(LINK.cc)  $^ $(LDLIBS) -o $@

 # etc....

I leave you to correct the other lines of your Makefile ... See also this answer ...

^{I corrected my make rules above : $^ has to be before $(LDLIBS) !}

BTW, remake is a nice tool to debug Makefile-s; for instance, with remake -x

这篇关于关于Makefile无法找到库的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！