C 编程奇怪的结构设置

Question

我正在尝试构建这个项目，但由于某种原因，程序在我运行时挂起。如果我注释掉数据缓存行，它工作正常。但它不能为两个不同的缓存调用 makeCache 我不知道为什么任何 C 专家都知道。我是 c 的新手。

   /*
 * main.c
 *
 *  Created on: Sep 16, 2010
 *      Author: TJ
 */
#include <stdlib.h>
#include <stdio.h>
typedef struct {
int tag;
int valid;
int LRU;
int offset;
}directoryBlock;

typedef struct{
int setNumber;
directoryBlock blocks[];
}cacheSet;

typedef struct{
int cacheNumber;
cacheSet *sets[];
}cache;

cache* makeCache(cache *makeMe,int numberOfSets, int blocksPerSet);


int main(void)
{
    int i = 0;
    //cache * temp = makeCache(10,200);
    i = 0;
    int j = 0;
    cache *instructions = malloc(sizeof(cache) + sizeof(cacheSet*));
    cache *data = malloc(sizeof(cache) + sizeof(cacheSet*));
    makeCache(instructions,20,300);
    makeCache(data,20,300);
    for(j=0;j < 20;j++)
            {
                for(i = 0; i < 300;i++)
                {
                    printf("Data From Set %d Block %d, Valid %d, Tag %d, LRU %d, Offset %d\n",j,i
                            ,instructions->sets[j]->blocks[i].valid,instructions->sets[j]->blocks[i].tag
                            ,instructions->sets[j]->blocks[i].LRU,instructions->sets[j]->blocks[i].offset);
                }
            }

    return 0;

}

cache* makeCache(cache *makeMe,int numberOfSets,int blocksPerSet)
{
    int i = 0;
    int j = 0;
    for(j=0; j < numberOfSets;j++)
    {

        cacheSet *newSet = malloc(sizeof(cacheSet) + sizeof(directoryBlock)*blocksPerSet);
        for(i = 0; i < blocksPerSet; i++)
        {
            directoryBlock temp;
            temp.LRU = i*j;
            temp.tag = i*j;
            temp.offset = i*j;
            temp.valid = i;
            newSet->blocks[i] = temp;
        }
        makeMe->sets[j] = newSet;
    }



    return makeMe;
}

Answer 1

您没有为 cacheSet 数组分配空间，您有 20 个 cacheSet，所以尝试将“20 *”添加到行中:

cache *instructions = malloc(sizeof(cache) + 20 *sizeof(cacheSet*));
cache *data = malloc(sizeof(cache) + 20 * sizeof(cacheSet*));