Boehm GC附带的“线”库导致了未定义的参考错误

我有一个使用Boehm GC的项目，所以我想我可能会使用它附带的cord字符串库。问题是我所有对cord函数的调用都会导致“未定义参考”错误。Boehm GC附带的“线”库导致了未定义的参考错误

我在/usr/lib（这是一个Linux系统）中有一个名为libcord.so的文件，我告诉CMake将目标链接到gc和cord。

从CMakeLists.txt

target_link_libraries(lang gc) 
target_link_libraries(lang cord)

从错误消息：：响应

编辑以＃1评论

../lib/liblang.so: undefined reference to `CORD_substr(char const*, unsigned long, unsigned long)' ../lib/liblang.so: undefined reference to `CORD_len(char const*)' ../lib/liblang.so: undefined reference to `CORD_cat(char const*, char const*)' ../lib/liblang.so: undefined reference to `CORD_cmp(char const*, char const*)' ../lib/liblang.so: undefined reference to `CORD_to_char_star(char const*)'

编辑回应评论＃2：

$ make -j4 VERBOSE=1 /usr/bin/cmake -H/home/michael/Projects/lang -B/home/michael/Projects/lang/build --check-build-system CMakeFiles/Makefile.cmake 0 /usr/bin/cmake -E cmake_progress_start /home/michael/Projects/lang/build/CMakeFiles /home/michael/Projects/lang/build/CMakeFiles/progress.marks /usr/bin/make -f CMakeFiles/Makefile2 all make[1]: Entering directory `/home/michael/Projects/lang/build' /usr/bin/make -f lib/CMakeFiles/lang.dir/build.make lib/CMakeFiles/lang.dir/depend make[2]: Entering directory `/home/michael/Projects/lang/build' cd /home/michael/Projects/lang/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /home/michael/Projects/lang /home/michael/Projects/lang/lib /home/michael/Projects/lang/build /home/michael/Projects/lang/build/lib /home/michael/Projects/lang/build/lib/CMakeFiles/lang.dir/DependInfo.cmake --color= make[2]: Leaving directory `/home/michael/Projects/lang/build' /usr/bin/make -f lib/CMakeFiles/lang.dir/build.make lib/CMakeFiles/lang.dir/build make[2]: Entering directory `/home/michael/Projects/lang/build' make[2]: Nothing to be done for `lib/CMakeFiles/lang.dir/build'. make[2]: Leaving directory `/home/michael/Projects/lang/build' /usr/bin/cmake -E cmake_progress_report /home/michael/Projects/lang/build/CMakeFiles 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 [ 94%] Built target lang /usr/bin/make -f src/CMakeFiles/main.dir/build.make src/CMakeFiles/main.dir/depend make[2]: Entering directory `/home/michael/Projects/lang/build' cd /home/michael/Projects/lang/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /home/michael/Projects/lang /home/michael/Projects/lang/src /home/michael/Projects/lang/build /home/michael/Projects/lang/build/src /home/michael/Projects/lang/build/src/CMakeFiles/main.dir/DependInfo.cmake --color= make[2]: Leaving directory `/home/michael/Projects/lang/build' /usr/bin/make -f src/CMakeFiles/main.dir/build.make src/CMakeFiles/main.dir/build make[2]: Entering directory `/home/michael/Projects/lang/build' Linking CXX executable lang cd /home/michael/Projects/lang/build/src && /usr/bin/cmake -E cmake_link_script CMakeFiles/main.dir/link.txt --verbose=1 /usr/bin/c++ CMakeFiles/main.dir/main.cpp.o -o lang -rdynamic ../lib/liblang.so -lgc -lcord -lgmp -Wl,-rpath,/home/michael/Projects/lang/build/lib ../lib/liblang.so: undefined reference to `CORD_substr(char const*, unsigned long, unsigned long)' ../lib/liblang.so: undefined reference to `CORD_len(char const*)' ../lib/liblang.so: undefined reference to `CORD_cat(char const*, char const*)' ../lib/liblang.so: undefined reference to `CORD_cmp(char const*, char const*)' make[2]: Leaving directory `/home/michael/Projects/lang/build' make[1]: Leaving directory `/home/michael/Projects/lang/build' ../lib/liblang.so: undefined reference to `CORD_to_char_star(char const*)' collect2: ld returned 1 exit status make[2]: *** [src/lang] Error 1 make[1]: *** [src/CMakeFiles/main.dir/all] Error 2 make: *** [all] Error 2

来源

2011-05-08 mtk358

，请复制粘贴在命令行CMake的运行时，它链接，和实际产出。 – 2011-05-08 20:35:59

对，现在你可以在详细模式下运行CMake或者其他东西来获得对gcc的实际调用或者它产生的任何东西吗？我想看看正在运行的命令，而不是CMake规则文件。 – 2011-05-08 21:01:53

从我所看到的，cord.h文件似乎并没有包含在它extern "C"语句，所以当你正在编译的名字改编正在做正确使用C++编译器的liblang.so。

在源在那里你#include <cord.h>你可能需要的东西，如：

extern "C" { 
#include "cord.h" 
}

来源

2011-05-08 22:10:46 msandiford

我实际上是在我的源文件中编写了原型，因为我的系统由于某种原因没有'cord.h'。尽管如此，“外部”C“”原型固定它。 – mtk358 2011-05-09 00:11:32

这可能会帮助您解决问题的CMake：

set_target_properties(<your target> 
    PROPERTIES 
    LINKER_LANGUAGE C)

来源

2011-05-09 06:52:28 arrowd

Boehm GC附带的“线”库导致了未定义的参考错误

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