删除指针导致堆损坏

Question

有人可以解释为什么这段代码会导致堆损坏吗？

string someText = "hello hello";
char **arrayOfCharPtr = new char*[5];
arrayOfCharPtr[0] = new char[someText.length()];
strcpy(arrayOfCharPtr[0], someText.c_str());
delete[] arrayOfCharPtr[0];

非常感谢！

Answer 1

您需要分配比字符串长度多一个字符来存储最后一个'\0'字符。

arrayOfCharPtr[0] = new char[someText.length()+1];

在您的情况下，strcpy 将在分配的块之后写入最后一个“\0”，这会破坏堆。

valgrind 等工具可以帮助理解。 valgrind 产生错误消息

==16970== Invalid write of size 1
==16970==    at 0x4C3106F: strcpy (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==16970==    by 0x400C47: main
==16970==  Address 0x5ab5cfb is 0 bytes after a block of size 11 alloc'd
==16970==    at 0x4C2E80F: operator new[](unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==16970==    by 0x400C1C: main

它定位了错误的来源。

删除指针导致堆损坏

Deleting pointer causes heap corruption

c++

pointers

strcpy

delete-operator

heap-corruption