pointer being realloc'd was not allocated,该如何解决

pointer being realloc'd was not allocated
if (_size >= _capacity) {
_capacity = _capacity * 5;
T* ptmp = (T*)realloc(_pt,  _capacity*sizeof(T));
if (ptmp) {
_pt = ptmp;
}
}


这段代码哪里有问题
------解决思路----------------------
你是不是在其他地方修改了_pt的值。然后把修改后的值传递给了realloc