Question

我正在使用FANN（http://leenissen.dk/fann/wp/download/）。这两个标题都可以在存档中找到，你可以在那里下载（我希望我不会给你带来太多麻烦）。

/* 
 * File:   main.cpp
 * Author: johannsebastian
 *
 * Created on November 26, 2013, 8:50 PM
 */

#include "../FANN-2.2.0-Source/src/include/doublefann.h"
#include "../FANN-2.2.0-Source/src/include/fann_cpp.h"
#include <cstdlib>
#include <iostream>


using namespace std;
using namespace FANN;

/*
 * 
 */

//Remember: fann_type is double!
int main(int argc, char** argv) {
    neural_net * N = new neural_net;
    const unsigned int myLayerArray[4] = {1,2,2,1};
    const unsigned int numLayers = 4;
    N->create_standard(3,1,2,1);
    cout<<"Easy!";
    return 0;
}

g ++说

"/usr/bin/make" -f nbproject/Makefile-Debug.mk QMAKE= SUBPROJECTS= .build-conf
make[1]: Entering directory `/home/johannsebastian/Desktop/heatmap3d/BACHnet/BACHnet'
"/usr/bin/make"  -f nbproject/Makefile-Debug.mk dist/Debug/GNU-Linux-x86/bachnet
make[2]: Entering directory `/home/johannsebastian/Desktop/heatmap3d/BACHnet/BACHnet'
mkdir -p build/Debug/GNU-Linux-x86
rm -f "build/Debug/GNU-Linux-x86/main.o.d"
g++    -c -g -MMD -MP -MF "build/Debug/GNU-Linux-x86/main.o.d" -o build/Debug/GNU-Linux-x86/main.o main.cpp
mkdir -p dist/Debug/GNU-Linux-x86
g++     -o dist/Debug/GNU-Linux-x86/bachnet build/Debug/GNU-Linux-x86/main.o 
build/Debug/GNU-Linux-x86/main.o: In function `FANN::neural_net::destroy()':
/home/johannsebastian/Desktop/heatmap3d/BACHnet/BACHnet/../FANN-2.2.0-Source/src/include/fann_cpp.h:915: undefined reference to `fann_get_user_data'
/home/johannsebastian/Desktop/heatmap3d/BACHnet/BACHnet/../FANN-2.2.0-Source/src/include/fann_cpp.h:919: undefined reference to `fann_destroy'
build/Debug/GNU-Linux-x86/main.o: In function `FANN::neural_net::create_standard_array(unsigned int, unsigned int const*)':
/home/johannsebastian/Desktop/heatmap3d/BACHnet/BACHnet/../FANN-2.2.0-Source/src/include/fann_cpp.h:979: undefined reference to `fann_create_standard_array'
collect2: error: ld returned 1 exit status
make[2]: *** [dist/Debug/GNU-Linux-x86/bachnet] Error 1
make[2]: Leaving directory `/home/johannsebastian/Desktop/heatmap3d/BACHnet/BACHnet'
make[1]: *** [.build-conf] Error 2
make[1]: Leaving directory `/home/johannsebastian/Desktop/heatmap3d/BACHnet/BACHnet'
make: *** [.build-impl] Error 2


BUILD FAILED (exit value 2, total time: 773ms)

你可以帮我解决这个问题吗？我想我可能有一些基本的编译器配置错误或其他什么。

Answer 1

编译器编译了您的代码。包括真的很有效。（但是，如果正确安装了库，则不必在那里指定完整路径，只需指定标题的名称。）
这是无法找到方法的链接器（ld）。
链接器出现问题，即您是否拥有带有方法定义的库，并在调用它时将其提供给链接器（在其选项中）。
您使用make文件，因此您必须指定选项（类似-lFANN）和库的路径（例如-L/path/path/path。。您也可以在$LD_LIBRARY_PATH系统中指定的路径变量，那么你不需要-L选项）。此外，您必须先安装（编译）库本身才能使用它。您有安装指南here。

该指南适合我：

下载FANN-2.2.0-Source。

使用cmake安装它：

[08:42:24]~/Downloads$ cd FANN-2.2.0-Source/
[08:42:27]~/Downloads/FANN-2.2.0-Source$ ls
CMakeLists.txt  README.txt  bin     datasets    src
COPYING.txt VS2010      cmake       examples
[08:42:27]~/Downloads/FANN-2.2.0-Source$ cmake .
-- The C compiler identification is GNU 4.7.3
-- The CXX compiler identification is GNU 4.7.3
-- Checking whether C compiler has -isysroot
-- Checking whether C compiler has -isysroot - yes
-- Checking whether C compiler supports OSX deployment target flag
-- Checking whether C compiler supports OSX deployment target flag - yes
-- Check for working C compiler: /opt/local/bin/gcc
-- Check for working C compiler: /opt/local/bin/gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Checking whether CXX compiler has -isysroot
-- Checking whether CXX compiler has -isysroot - yes
-- Checking whether CXX compiler supports OSX deployment target flag
-- Checking whether CXX compiler supports OSX deployment target flag - yes
-- Check for working CXX compiler: /<...>g++
-- Check for working CXX compiler: /<...>g++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- FANN is used as APPLICATION_NAME
-- Configuring done
-- Generating done
-- Build files have been written to: /Users/ikulakov/Downloads/FANN-2.2.0-Source
[08:43:57]~/Downloads/FANN-2.2.0-Source$ make
Scanning dependencies of target doublefann
[ 25%] Building C object src/CMakeFiles/doublefann.dir/doublefann.c.o
Linking C shared library libdoublefann.dylib
[ 25%] Built target doublefann
Scanning dependencies of target fann
[ 50%] Building C object src/CMakeFiles/fann.dir/floatfann.c.o
Linking C shared library libfann.dylib
[ 50%] Built target fann
Scanning dependencies of target fixedfann
[ 75%] Building C object src/CMakeFiles/fixedfann.dir/fixedfann.c.o
Linking C shared library libfixedfann.dylib
[ 75%] Built target fixedfann
Scanning dependencies of target floatfann
[100%] Building C object src/CMakeFiles/floatfann.dir/floatfann.c.o
Linking C shared library libfloatfann.dylib
[100%] Built target floatfann
[08:44:02]~/Downloads/FANN-2.2.0-Source$ sudo make install

Answer 2

在您的情况下，不是编译器，但链接器无法找到该功能。

您满意的编译器包括包含您使用的函数声明的文件，并指定包含文件的目录。

链接器想要查看包含代码编译定义的实际库。

您可能必须在链接器命令行上指定-lfann（对于在-l之后使用的确切名称，请参阅实际调用的库 - 如果它被称为libfann.so，请使用以上参数）。

如果库安装在默认目录中，那么这应该足够了;否则你可能还需要-L参数指向包含库的路径（当然，必须首先编译库）。

即使包含g ++，g ++也找不到这种方法

2 个答案: