Question

我想拥有一个读取文件并以char字符串的char（string）数组返回特定行的函数。

我跑了Valgrind，它表明障碍物确实丢失了，我不明白为什么。

如果我在分配内存的同一块中直接调用frees，则所有内容都将释放。如果我在块外（在另一个函数中）执行此操作，则Valgrind肯定会丢失。

我丢失了字节的代码：

int read_file(char *filename, char * search, char **data)
{
    int counter = 0;
    int size = 1;
    FILE *file;
    file = fopen(filename, "r");
    char c[100];

    while(fgets(c,100, file))
    {
        if(strstr(c,search))
        {
            while(fgets(c, 100, file))
            {
                if(c[0] == '[')
                {
                    break;
                }
                if(c[0] == '\n')
                {
                    continue;
                }
                if(counter+1 > size)
                {
                    data = realloc(data,++size);
                }
                data[counter] = malloc(sizeof(**data)*(strlen(c)+1));
                memcpy(data[counter], c, strlen(c)+1);
                counter++;
            }
        }
    }
    fclose(file);
    return size;
}

void free_pointer(char **data, int size)
{
    for(int i = 0; i < size; ++i)
    {
        free(data[i]);
    }
    free(data);
}

int main()
{
    char **data = malloc(sizeof(*data));
    int x = read_file("test.txt", "omg", data);

//  for(int i = 0; i < x; ++i)
//  {
//      printf("%s", data[i]);
//  }
    free_pointer(data,x);
    return 0;
}

Valgrind显示以下内容：

泄漏摘要：
  == 17349 ==绝对丢失：3个块中的20个字节
  == 17349 ==间接丢失：0个字节（0块）
  == 17349 ==可能丢失：0字节，共0块
  == 17349 ==仍可访问：0个字节（0块）
  == 17349 ==已禁止：0字节，0块

当我在此处添加自由行时：


    if(counter+1 > size)
    {
        data = realloc(data,++size);
    }
    data[counter] = malloc(sizeof(**data)*(strlen(c)+1));
    memcpy(data[counter], c, strlen(c)+1);
    //if i add this
    free(data[counter]);
    counter++;

    free(data);
    fclose(file);
    return size;

Valgrind显示以下内容：

堆摘要：
  == 17459 ==在出口处使用：0字节，0块中
  == 17459 ==堆总使用量：8个分配，8个空闲，分配的4,684个字节

更新

Valgrind的第一个错误：

Valgrind erros:  
==22271== Invalid read of size 8  
==22271==    at 0x10946C: main (in main)  
==22271==  Address 0x4a34480 is 0 bytes inside a block of size 8 free'd  
==22271==    at 0x4837D7B: realloc (vg_replace_malloc.c:826)  
==22271==    by 0x109299: read_file (in main)  
==22271==    by 0x10944B: main (in main)  
==22271==  Block was alloc'd at  
==22271==    at 0x483577F: malloc (vg_replace_malloc.c:299)  
==22271==    by 0x109426: main (in main)

由于我更改为正确的重新分配大小，所以出现了更多错误

==22271== LEAK SUMMARY:
==22271==    definitely lost: 24 bytes in 1 blocks
==22271==    indirectly lost: 17 bytes in 2 blocks
==22271==      possibly lost: 0 bytes in 0 blocks
==22271==    still reachable: 0 bytes in 0 blocks
==22271==         suppressed: 0 bytes in 0 blocks

Valgrind显示肯定丢失了字节，但应该免费吗？

更新

0 个答案: