[RTT例程练习] 3.2 动态内存管理之rt_realloc和free

realloc 用于重新分配内存的场景。如果原先通过 malloc分配的空间过小，则可通过realloc重新分配大小。当然具体实现的时候分两种情况，如果原内存块后有足够的空间，则之间将原内存块扩大，如果不够，则重新寻找一个地方，将原数据也拷贝至此。

代码：

#include <rtthread.h>struct rt_thread thread1;static rt_uint8_t thread1_stack[512];void thread1_entry(void* parameter){    int i,j = 1;    char *ptr[10]; /* 用于放置10个分配内存块的指针*/    /* 对指针清零*/    for (i = 0; i <10; i ++)    ptr[i] = RT_NULL;    while(j--)    {        for (i = 0; i <10; i++)        {            /* 每次分配(1 <<i)大小字节数的内存空间*/            ptr[i] = rt_malloc(10);            /* 如果分配成功*/                        if (ptr[i] != RT_NULL)            {                rt_kprintf("get memory: 0x%x\n", ptr[i]);                rt_realloc(ptr[i],16);                /* 如果分配成功*/                if (ptr[i] != RT_NULL)                {                    rt_kprintf("memory realloc success!\n");                    /* 释放内存块*/                    rt_free(ptr[i]);                    rt_kprintf("memory free success!\n");                    ptr[i] = RT_NULL;                }            }        }    }}int rt_application_init(){    rt_thread_init(&thread1,        "thread1",        thread1_entry, RT_NULL,        &thread1_stack[0], sizeof(thread1_stack),        10, 100);    rt_thread_startup(&thread1);        return 0;}

结果：

get memory: 0x20000c58memory realloc success!memory free success!get memory: 0x20000c58memory realloc success!memory free success!get memory: 0x20000c58memory realloc success!memory free success!get memory: 0x20000c58memory realloc success!memory free success!get memory: 0x20000c58memory realloc success!memory free success!get memory: 0x20000c58memory realloc success!memory free success!get memory: 0x20000c58memory realloc success!memory free success!get memory: 0x20000c58memory realloc success!memory free success!get memory: 0x20000c58memory realloc success!memory free success!get memory: 0x20000c58memory realloc success!memory free success!