win7+android+studio 编译问题咨询

[xiangdeyizhang]

../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_M_destroy(std::allocator const&)'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_M_destroy(std::allocator const&)'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_S_empty_rep_storage'

你好，作者，我在windows上用AS直接打开你的工程编译，现在有如下错误，这个是因为你的libncnn的路径是用这个编译的吗？

[iscas-lee]

same question.

../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_M_destroy(std::allocator const&)'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_M_destroy(std::allocator const&)'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_S_empty_rep_storage'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_S_empty_rep_storage'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::clear(): error: undefined reference to 'std::string::_Rep::_M_destroy(std::allocator const&)'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::clear(): error: undefined reference to 'std::string::_Rep::_S_empty_rep_storage'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::load_param(__sFILE*): error: undefined reference to 'std::string::_Rep::_M_destroy(std::a

[guanbo123456]

same question.

../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_M_destroy(std::allocator const&)'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_M_destroy(std::allocator const&)'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_S_empty_rep_storage'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::~Net(): error: undefined reference to 'std::string::_Rep::_S_empty_rep_storage'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::clear(): error: undefined reference to 'std::string::_Rep::_M_destroy(std::allocator const&)'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::clear(): error: undefined reference to 'std::string::_Rep::_S_empty_rep_storage'
../../../../src/main/jniLibs/armeabi-v7a/libncnn.a(net.cpp.o):D:/ncnn/src/net.cpp:function ncnn::Net::load_param(__sFILE*): error: undefined reference to 'std::string::_Rep::_M_destroy(std::a

[Augnine]

I have solved it! I rebuild the lib in my own computer.

[saeedkhanehgir]

@zchfaq hi
can i question how you can rebuild?

[saeedkhanehgir]

@zchfaq rebuild libncnn.a ? or use again bazel build -c opt --cxxopt='--std=c++11' --fat_apk_cpu=x86,x86_64,arm64-v8a,armeabi-v7a
//tensorflow/contrib/lite/examples/android:tflite_demo with your own ndk and sdk api level?

[zlszhonglongshen]

I have solved it! I rebuild the lib in my own computer.

你能分享一下 是怎么编译的嘛？

[Augnine]

@saeedkhanehgir @zlszhonglongshen
It has been a long time and I forget it, I am very sorry!

[ZivenMan]

无法编译，提示ncnn中的一些函数无法链接，是因为你用的NDK版本跟ncnn库编译时用的NDK版本不一致，建议r16b的NDK，我试过，跟作者提供的ncnn库匹配。
另外还要注意，如果你是用android 10测试，会存在读取不到模型文件的问题，那是因为Android Q文件存储机制修改成了沙盒模式，操作拍照，或者上传，报错，打日志，获取相片的路径为空，解决办法：
在AndroidManifest.xml 里的application中添加 android:requestLegacyExternalStorage=“true” 临时解决。可以兼容到Android 11。或者targetsdk 降低到29以下。参见：https://blog.csdn.net/yhx956058885/article/details/107359184/