c++ - gcc 11 版本的协议(protocol)中 undefined symbol

Question

我正在尝试按照 these instructions. 构建 Protocol Buffer

这就是我所做的。

git clone https://github.com/protocolbuffers/protobuf.git
cd protobuf
git submodule update --init --recursive
./autogen.sh
./configure
make -j6

成功构建后，我检查了

ldd -d src/.libs/protoc

它显示了很多 undefined symbol 。

root@renju-mc:~/.../protobuf# ldd -d src/.libs/protoc
        linux-vdso.so.1 (0x00007fff1f3a5000)
        libprotoc.so.28 => not found
        libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fdce230c000)
        libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fdce20f4000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fdce1d03000)
        libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fdce1965000)
        /lib64/ld-linux-x86-64.so.2 (0x00007fdce291d000)
undefined symbol: _ZN6google8protobuf8compiler20CommandLineInterface12AllowPluginsERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE       (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler20CommandLineInterface3RunEiPKPKc (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler20CommandLineInterfaceD1Ev        (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler6csharp9GeneratorC1Ev     (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler6python9GeneratorC1Ev     (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler20CommandLineInterface17RegisterGeneratorERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESA_PNS1_13CodeGeneratorESA_   (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler20CommandLineInterfaceC1Ev        (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler4java13JavaGeneratorD1Ev  (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler13CodeGeneratorD2Ev       (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler4java15KotlinGeneratorC1Ev        (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler6csharp9GeneratorD1Ev     (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler3cpp12CppGeneratorD1Ev    (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler10objectivec19ObjectiveCGeneratorC1Ev     (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler4java15KotlinGeneratorD1Ev        (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler10objectivec19ObjectiveCGeneratorD1Ev     (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler3cpp12CppGeneratorC1Ev    (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler4java13JavaGeneratorC1Ev  (src/.libs/protoc)
undefined symbol: _ZN6google8protobuf8compiler6python9GeneratorD1Ev     (src/.libs/protoc)

libprotoc.so.28 => 未找到 此文件与 protoc 位于同一位置。

root@renju-mc:~/.../protobuf# ls -l src/.libs/libprotoc.so.28
lrwxrwxrwx 1 root root 19 Jul 25 22:20 src/.libs/libprotoc.so.28 -> libprotoc.so.28.0.3

我使用的是 Ubuntu 18.04，带有 gcc-11。

gcc version 11.1.0 (Ubuntu 11.1.0-1ubuntu1~18.04.1)

Answer 1

默认情况下，Linux 加载程序 ld.so 不会从当前目录加载库，而仅从预定义位置加载。

您正在尝试从当前目录加载依赖于当前目录中另一个库的库，因此加载失败。

ld.so 的手册页解释 how to set LD_LIBRARY_PATH in order change this behavior .