c++ - 如何将 SunriseDD C 库与 C++ 应用程序链接？

Question

我一直在寻找 C 或 C++ 中的无锁哈希表实现，并找到了一个:SunriseDD .这是个好消息 :) 几天来，我一直在努力启动并运行它，但没有成功。我可以使用 GCC C 编译器将下载的源代码编译为静态库。我得到了 libSunriseDD.a 存档。

到目前为止还不错 :D我创建了一个简单的 C++ 应用程序来包装哈希表的 SunriseDD C 实现。这是 main.cpp:

#include <iostream>
#include <dd_data_dictionary.h>

using namespace std;

struct Node{
    int oid;
    int x, y;
};    
struct HashTableEntry{
    Node *node;
    int idx;
};
void copyFunction(void * source, void * target){
    target = source;
}

template<typename T>class HashTableDD{
private:
    dd_dictionary objects;
public:
    HashTableDD() {
        objects = dd_new_dictionary(); // creating dictionary
        dd_set_object_copy_function_for_dictionary(objects, copyFunction); // setting copy function
    }
    ~HashTableDD() {
        dd_dispose_dictionary(objects);
    }    
    bool insert(T obj, long key){
        return dd_add_object_for_key(objects, (char *)key, (void*)obj);
    }
    bool remove(long key){
        return dd_remove_object_for_key(objects, (char *)key);
    }
    T find(long key) {
        return (T)dd_object_for_key(objects, (char *)key, false);
    }
};    

int main(int argc, char ** argv){
    HashTableDD<HashTableEntry*> *ht = new HashTableDD<HashTableEntry*>();
    HashTableEntry* hte = new HashTableEntry;
    hte->idx = 1;
    hte->node = NULL;
    ht->insert(hte, 1);
    HashTableEntry* hte2 = new HashTableEntry;
    hte2->idx = 2;
    Node n;
    n.oid = 10; n.x = 10; n.y = 10;
    hte2->node = &n;
    ht->insert(hte2, 2);

    HashTableEntry* ret = ht->find(1);   
    if(ret != NULL){
        cout << "hte. idx: " << ret->idx << " node: " << ret->node << endl;
    }    
    ht->remove(1);
    ht->remove(2);    
    delete hte; delete hte2; delete ht;
    return 0;
}

但是链接器对此并不满意:

:~/Desktop/HashTable$ make
Building file: main.cpp
Invoking: GCC C++ Compiler
g++ -ISunriseDD/build/../ -O0 -g3 -m64 -c -o"build/main.o" "main.cpp"
Finished building: main.cpp

Building target: build/HashTableDD
Invoking: GCC C++ Linker
g++ -LSunriseDD/build/ -lSunriseDD -o build/HashTableDD build/main.o
build/main.o: In function `HashTableDD':
/home/robertas/Desktop/HashTable/main.cpp:32: undefined reference to `dd_new_dictionary()'
/home/robertas/Desktop/HashTable/main.cpp:33: undefined reference to `dd_set_object_copy_function_for_dictionary(void*, void (*)(void*, void*))'
build/main.o: In function `HashTableDD<HashTableEntry*>::insert(HashTableEntry*, long)':
/home/robertas/Desktop/HashTable/main.cpp:40: undefined reference to `dd_add_object_for_key(void*, char const*, void*)'
build/main.o: In function `HashTableDD<HashTableEntry*>::find(long)':
/home/robertas/Desktop/HashTable/main.cpp:47: undefined reference to `dd_object_for_key(void*, char const*, bool)'
build/main.o: In function `HashTableDD<HashTableEntry*>::remove(long)':
/home/robertas/Desktop/HashTable/main.cpp:44: undefined reference to `dd_remove_object_for_key(void*, char const*)'
build/main.o: In function `~HashTableDD':
/home/robertas/Desktop/HashTable/main.cpp:36: undefined reference to `dd_dispose_dictionary(void*)'
collect2: ld returned 1 exit status
make: *** [build/HashTableDD] Error 1

知道我在这里做错了什么吗？我是否错误地链接了 SunriseDD 库？

顺便说一句，我的 main.cpp 所在的目录列表如下:

+HashTable
|--+build
|   |--main.o
|---main.cpp
|--+SunriseDD
   |--+build
   |  |--libSunriseDD.a
   |  |--other object files
   |--headers and source files of SunriseDD 

感谢您的帮助!

Answer 1

将 -lSunriseDD last 放在链接器行上。链接器从左到右处理参数，并在处理静态库时在库中搜索当前 undefined symbol 。

另外，除非库支持 C++，否则 wrap 包含在 extern "C" 中。

extern "C" {
  #include <dd_data_dictionary.h>
}