C++ 在C+;中对new和delete进行过度编码导致通用内存分配崩溃+;
我有以下代码。当我删除分配的内存(即Rational::deleteMemPool())时,以下代码崩溃 将输出作为 mempool值为00000000 mempool值为003462E8 mempool值为003462E8 //虽然我们有有效的指针,但这里是用于删除崩溃的 谁能帮帮我这里有什么臭虫吗C++ 在C+;中对new和delete进行过度编码导致通用内存分配崩溃+;,c++,C++,我有以下代码。当我删除分配的内存(即Rational::deleteMemPool())时,以下代码崩溃 将输出作为 mempool值为00000000 mempool值为003462E8 mempool值为003462E8 //虽然我们有有效的指针,但这里是用于删除崩溃的 谁能帮帮我这里有什么臭虫吗 #include <string> #include <iostream> template < class T > class MemoryPool {
#include <string>
#include <iostream>
template < class T >
class MemoryPool {
public:
MemoryPool (size_t size = EXPANSION_SIZE);
~MemoryPool ();
inline void* alloc (size_t size); // Allocate a T element from the free list.
inline void free (void *someElement); // Return a T element to the free list.
private:
MemoryPool<T> *next; // next element on the free list.
enum { EXPANSION_SIZE = 32}; // If the freeList is empty, expand it by this amount.
void expandTheFreeList(int howMany = EXPANSION_SIZE); // Add free elements to the free list
};
template < class T > MemoryPool < T > :: MemoryPool (size_t size) {
expandTheFreeList(size);
}
template < class T > MemoryPool < T > :: ~MemoryPool () {
MemoryPool<T> *nextPtr = next;
for (nextPtr = next; nextPtr != NULL; nextPtr = next) {
next = next->next;
delete [] nextPtr;
}
}
template < class T > inline void* MemoryPool < T > :: alloc (size_t) {
if (!next) {
expandTheFreeList();
}
MemoryPool<T> *head = next;
next = head->next;
return head;
}
template < class T > inline void MemoryPool < T > :: free (void *doomed) {
MemoryPool<T> *head = static_cast <MemoryPool<T> *> (doomed);
head->next = next;
next = head;
}
template < class T > void MemoryPool < T > :: expandTheFreeList(int howMany) {
// We must allocate an object large enough to contain the next pointer.
size_t size = (sizeof(T) > sizeof(MemoryPool<T> *)) ? sizeof(T) : sizeof(MemoryPool<T> *);
void *pNewAlloc = new char[size];
MemoryPool<T> *runner = static_cast <MemoryPool<T> *> (pNewAlloc);
next = runner;
for (int i = 0; i < howMany ; i++) {
void *pNewAlloc = new char[size];
runner->next = static_cast <MemoryPool<T> *> (pNewAlloc);
runner = runner->next;
}
runner->next = 0;
}
class Rational {
public:
Rational (int a = 0, int b = 1 ) : n(a), d(b) {}
void *operator new(size_t size) { return memPool->alloc(size); }
void operator delete(void *doomed,size_t size) { memPool->free(doomed); }
static void newMemPool() {
std::cout << "mempool value is " << Rational::memPool << std::endl;
memPool = new MemoryPool <Rational>;
std::cout << "mempool value is " << Rational::memPool << std::endl;
}
static void deleteMemPool() {
std::cout << "mempool value is " << Rational::memPool << std::endl;
delete memPool;
}
private:
int n; // Numerator
int d; // Denominator
static MemoryPool <Rational> *memPool;
};
MemoryPool <Rational> *Rational::memPool = 0;
int main() {
Rational *array[1000];
Rational::newMemPool();
// Start timing here
for (int j = 0; j < 1; j++) {
for (int i = 0; i < 10; i++) {
array[i] = new Rational(i);
}
for (int i = 0; i < 10; i++) {
delete array[i];
}
}
// Stop timing here
Rational::deleteMemPool();
}
您在删除内存池中的块时遇到问题。分配块时,使用
expandthefleelist(i)
中的newchar[size]
但是当您删除这些块时,您使用delete[]nextPtr
:
template < class T > MemoryPool < T > :: ~MemoryPool () {
MemoryPool<T> *nextPtr = next;
for (nextPtr = next; nextPtr != NULL; nextPtr = next) {
next = next->next;
delete [] nextPtr; // <-- problem
}
}
似乎使事情不会崩溃。当然,可能还有其他问题。您在删除内存池中的块时遇到了问题。分配块时,使用
expandthefleelist(i)
中的newchar[size]
但是当您删除这些块时,您使用delete[]nextPtr
:
template < class T > MemoryPool < T > :: ~MemoryPool () {
MemoryPool<T> *nextPtr = next;
for (nextPtr = next; nextPtr != NULL; nextPtr = next) {
next = next->next;
delete [] nextPtr; // <-- problem
}
}
似乎使事情不会崩溃。当然,可能还有其他问题。是否有堆栈跟踪?堆栈跟踪:>ReadParsing.exe!Real::DeleTeMeMoPoO()75行C++ + RealPr.NeX.EXE!(107)C++ C++ RealPrace.exe!tmainCRTStartup()行586+0x19字节C ReadParsing.exe!mainCRTStartup()行403 C kernel32.dll!7c817077()我已经为您编辑了您的问题,以易于阅读的格式添加了stacktrace。好的,哪一行是第75行?第75行是delete memPool;在deleteMemPool函数中。是否获得堆栈跟踪?堆栈跟踪:>ReadParsing.exe!Real::DeleTeMeMoPoO()75行C++ + RealPr.NeX.EXE!(107)C++ C++ RealPrace.exe!tmainCRTStartup()行586+0x19字节C ReadParsing.exe!mainCRTStartup()行403 C kernel32.dll!7c817077()我已经为您编辑了您的问题,以易于阅读的格式添加了stacktrace。好的,哪一行是第75行?第75行是delete memPool;在deleteMemPool函数中。
delete [] reinterpret_cast<char*>(nextPtr);