c - 仅在一个函数中出现 "variable_name"未声明错误

Question

我在尝试诊断代码中的错误时遇到了一些麻烦。由于某种原因，编译器认为我在声明它的地方有一个未声明的变量。我找不到解决方案。

struct node {
    int size_chunk_memory;
    //1 = free, 0= used
    int is_free; 
    struct node *next;
    struct node *prev;
};

void merge(void* address) {
    if (address == 0) {
        return;
    }
    struct node* curr_merge = (struct node*)address;
    struct node* prev_merge = curr_merge->prev;
    struct node* next_merge = curr_merge->next;

    if (curr_merge->is_free == 1 &&  prev_merge->is_free == 1) {
        prev_merge->size_chunk_memory = size_chunk_memory + curr_merge->size_chunk_memory + sizeof(struct node);
        prev_merge->next = curr_merge->next;
        curr_merge = prev_merge;
    }
    if (curr_merge->is_free == 1 && next_merge->is_free == 1) {
        curr_merge->size_chunk_memory = size_chunk_memory + next_merge->size_chunk_memory + sizeof(struct node);
        curr_merge->next = next_merge->next;
    }
}

这是我收到的错误:

 ‘size_chunk_memory’ undeclared (first use in this function)
(Each undeclared identifier is reported only once
for each function it appears in.)

由于篇幅原因，我省略了很多程序。如果您需要更多信息，请告诉我。

非常感谢。

Answer 1

prev_merge->size_chunk_memory = size_chunk_memory + curr_merge->size_chunk_memory + sizeof(struct node);

curr_merge->size_chunk_memory = size_chunk_memory + next_merge->size_chunk_memory + sizeof(结构节点);

您可以在结构引用之外访问它。您需要以与 size_chunk_memory 的其他用途相同的方式访问它，即通过 struct node 指针和 ->。