Question

我的目标是创建一个.dat文件，其中包含100个空记录。我已经使用以下代码启动了该程序：

void* kalloc(int _size) {
    void* ptr = NULL;  
    struct ListNode* freeMem = kallocator.free_memory;
    struct ListNode* allocMem = kallocator.allocated_memory;
    struct KBlock* freeBlock;
    freeBlock = freeMem->item;
    struct KBlock* allocBlock = (struct KBlock*) malloc(sizeof(struct KBlock));
    if(kallocator.aalgorithm == FIRST_FIT){
        while(freeMem){
            if(freeBlock->size >= _size){
                allocBlock->size = _size;
                allocBlock->address = freeBlock->address;
                struct ListNode* listnode = List_createNode(allocBlock);
                List_insertTail(&allocMem, listnode);
                printf("size of freeBlock: %d\n", freeBlock->size);
                printf("address of freeBlock: %p\n", freeBlock->address);
                ptr = freeBlock->address;
                printf("Pointer value: %p\n", ptr);
                freeBlock->address = freeBlock->address + _size;
                allocMem = allocMem->next;
                freeBlock->size = freeBlock->size - _size;
                printf("allocBlock size: %d\n", allocBlock->size);
            }
            else{
                printf("Not enough space in memory\n");
                return NULL;
            }
            freeMem = freeMem->next;
        }

    }
    else if(kallocator.aalgorithm == BEST_FIT){

    }
    else if(kallocator.aalgorithm == WORST_FIT){

    }
    else{
        printf("No algorithm chosen\n");
        exit(-1);
    }

    // Allocate memory from kallocator.memory 
    // ptr = address of allocated memory
    return ptr;
}

我得到一个.dat输出，但是当我打开它以检查所有项目都为NULL时，它们下面有角色。如何检查这是否是垃圾值，或者我实际上是将100个结构初始化为空白？

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Answer 1

struct item createEmptyRecord = {0, "", "", 0.0};

请注意，您在此处传递""来初始化int成员。字符串文字""与NULL不同。如果您提高编译器的警告级别，它应警告您将const char*转换为int。

将结构初始化为全零的正确方法是：

struct item createEmptyRecord = {0};

或者您可以使用memset：

struct item createEmptyRecord;
memset(&createEmptyRecord, 0, sizeof(createEmptyRecord));

用空结构填充dat文件

1 个答案: