2

我尝试构建 boost asio 示例提供的示例代码：http: //www.boost.org/doc/libs/1_54_0/doc/html/boost_asio/example/cpp11/spawn/echo_server.cpp

我把所有的代码复制到一个cpp文件中，在linux上用gcc4.7和cmake编译，用boost协程和boost上下文库链接，但是链接失败。

输出如下：

Linking CXX executable ../../../output/bin/unit_test
cd /home/watson/ID_project/build/server_linux_makefile_gcc/abc/test/unit/abc_async && /usr/local/bin/cmake -E cmake_link_script CMakeFiles/unit_test.dir/link.txt --verbose=1
/usr/bin/c++   -std=c++11 -O3 -DNDEBUG  -pthread -lrt -ltcmalloc -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-free CMakeFiles/unit_test.dir/TestFileChannel.cpp.o CMakeFiles/unit_test.dir/TestStreamBuffer.cpp.o CMakeFiles/unit_test.dir/TestTimer.cpp.o CMakeFiles/unit_test.dir/TestThreadPool.cpp.o CMakeFiles/unit_test.dir/TestScheduler.cpp.o CMakeFiles/unit_test.dir/PCH.cpp.o CMakeFiles/unit_test.dir/main.cpp.o CMakeFiles/unit_test.dir/TestUDPNetwork.cpp.o CMakeFiles/unit_test.dir/TestTCPNetwork.cpp.o  -o ../../../output/bin/unit_test -rdynamic ../../../../../../install/thirdparty_linux_makefile_gcc/lib/libboost_unit_test_framework-gcc47-mt-1_54.a ../../../../../../install/thirdparty_linux_makefile_gcc/lib/libboost_context-gcc47-mt-1_54.a ../../../../../../install/thirdparty_linux_makefile_gcc/lib/libboost_coroutine-gcc47-mt-1_54.a ../../../../../../install/thirdparty_linux_makefile_gcc/lib/libboost_thread-gcc47-mt-1_54.a ../../../../../../install/thirdparty_linux_makefile_gcc/lib/libboost_filesystem-gcc47-mt-1_54.a ../../../../../../install/thirdparty_linux_makefile_gcc/lib/libyaml-cpp.a ../../../../../../install/thirdparty_linux_makefile_gcc/lib/libmongoc.a ../../../../../../install/thirdparty_linux_makefile_gcc/lib/libboost_system-gcc47-mt-1_54.a ../../../../../../install/thirdparty_linux_makefile_gcc/lib/libprotobuf.a
../../../../../../install/thirdparty_linux_makefile_gcc/lib/libboost_coroutine-gcc47-mt-1_54.a(coroutine_context.o): In function `boost::coroutines::detail::coroutine_context::coroutine_context(void (*)(long), boost::coroutines::stack_context*)':
coroutine_context.cpp:(.text+0x103): undefined reference to `make_fcontext'
../../../../../../install/thirdparty_linux_makefile_gcc/lib/libboost_coroutine-gcc47-mt-1_54.a(coroutine_context.o): In function `boost::coroutines::detail::coroutine_context::jump(boost::coroutines::detail::coroutine_context&, long, bool)':
coroutine_context.cpp:(.text+0x1bc): undefined reference to `jump_fcontext'
collect2: error: ld returned 1 exit status
make[2]: *** [abc/output/bin/unit_test] Error 1

我从 .a 文件中打印符号表，发现符号jump_fcontext' andmake_fcontext' 存在：

nm libboost_context-gcc47-mt-1_54.a

make_x86_64_sysv_elf_gas.o:
                 U _GLOBAL_OFFSET_TABLE_
                 U _exit
000000000000002e t finish
0000000000000000 T make_fcontext

jump_x86_64_sysv_elf_gas.o:
0000000000000000 T jump_fcontext

有人可以给我任何提示吗？我尝试谷歌每个地方，但没有信息。

4

2 回答 2

8

boost_context尝试交换和的链接顺序boost_coroutine。

链接器文档指出：

[...] 链接器按照指定的顺序搜索和处理库和目标文件。因此，“foo.o -lz bar.o”在文件 foo.o 之后但在 bar.o 之前搜索库“z”。如果 bar.o 引用 'z' 中的函数，则可能不会加载这些函数。

在这种情况下 Boost.Coroutine依赖于Boost.Context。因此，链接时boost_coroutine应该出现在之前boost_context。有关更多链接器订购详细信息，请考虑阅读此答案。

于 2013-07-26T13:52:46.747 回答
0

Just to add another possibility for this (specifically with the Boost Context library) - if building under MinGW on Windows, using an earlier version of MASM can produce static libraries that contain no linkable symbols due to the way the symbols are exported.

The solution is to rebuild Boost Context with MASM 8.

See the answer at https://stackoverflow.com/a/26874113/1678468 for more about this.

于 2014-11-11T22:38:29.887 回答