constructor the shared structure in-place

new(mCblk) audio_track_cblk_t();   placement new

#include <iostream>
#include <stdio.h>
#include <malloc.h>

class Student
{
    private:
        int age;
        int grade;
    public:
        Student(void)
        {
            age = 5;
            grade = 10;
        }

        ～Student(void)
        {
            printf("xx\n");
        }
};

int main(void)
{
    Student *pStudent = (Student*)malloc(sizeof(Student));
    char *p = (char*)pStudent;

    int i = 0;
    for(i = 0; i < sizeof(Student); i++)
         *p++ = 0;

    p = (char*)pStudent;

    new(pStudent) Student();

   for(i = 0; i < sizeof(Student); i++)
   {
        printf("%u\n", (unsigned int)(*p) & off);
        p++;
   }
   delete pStudent;
   return 0;
}

x86结果：
5
0
0
0
10
0
0
0