c++ - C++中带有模板初始化的静态结构指针

我正在实现一个简单的MemPool。 MemPool以LinkList的形式实现。但我不知道宣布static Node * free_mem_head;正确地。template <int PIECE_SIZE>class mempool {private: struct Node { Node * next; char p_mem[PIECE_SIZE]; }; const static size_t bunch_size = 50;public: static Node * free_mem_head; mempool(); ~mempool(); void * allocate(); void deallocate(void *);};template <int PIECE_SIZE>mempool<PIECE_SIZE>::mempool() {}template <int PIECE_SIZE>mempool<PIECE_SIZE>::~mempool() {}template <int PIECE_SIZE>void* mempool<PIECE_SIZE>::allocate() { if (free_mem_head == NULL) { size_t size_to_new = bunch_size * sizeof(Node); void *new_mem = ::operator new(size_to_new); free_mem_head = static_cast<Node*>(new_mem); for (int i = 0; i<bunch_size - 1; i++) { free_mem_head[i].next = &free_mem_head[i + 1]; } free_mem_head[bunch_size - 1].next = NULL; Node *res = free_mem_head; free_mem_head = free_mem_head->next; } else { Node * res = free_mem_head; free_mem_head = free_mem_head->next; return res; }}template <int PIECE_SIZE>void mempool<PIECE_SIZE>::deallocate(void * node_to_free) { Node * p = static_cast<Node*> (node_to_free); p->next = free_mem_head; p = free_mem_head;}这就是我的使用方式:#include <cstring>class Test {public: Test(int a, int b) :a(a), b(b) { strncpy(c, "abc", 3); c[3] = 0; } int a; double b; char c[100];private: void *operator new(size_t s1); void operator delete(void *);};和class Node;mempool<sizeof(Test)> mempool1;Node * mempool<sizeof(Test)>::free_mem_head = NULL;void * Test::operator new(size_t s1) { return mempool1.allocate();}void Test::operator delete(void *p) { mempool1.deallocate(p); return;}它有编译错误:错误:专用成员“mempool ::free_mem_head”需要使用“template ”语法 节点* mempool::free_mem_head = NULL; (adsbygoogle = window.adsbygoogle || []).push({}); 最佳答案 您应定义free_mem_head而不进行专门化:template<int PIECE_SIZE>typename mempool<PIECE_SIZE>::Node * mempool<PIECE_SIZE>::free_mem_head{};使用C++ 17可以在模板本身内部定义:static inline Node * free_mem_head{}; (adsbygoogle = window.adsbygoogle || []).push({});