Is this a valid way of defining a struct that references a node of the same type?

Question

The structure I want is a linked-list. Each block contains a header and a block_part. The header contains free, prev, and next. I'm just wondering if the code below is a valid implementation.

typedef struct block
{
    /*header + block*/
    bool free;
    block *prev;
    block *next;
    char block_part[];
} block;

In response to the comments, so the correct way to do this is :

typedef struct block block;

struct block
{
    /*header + block*/
    bool free;
    block *prev;
    block *next;
    char block_part[];
} ;

?

Not in C; you need to use `struct block *` inside the structure definition. Or you need `typedef struct block block;` followed by `struct block { …; block *next; … };`. The story is different in C++. — Jonathan Leffler, Mar 22 '16 at 06:46
That is one of the two valid ways to do it. The other was `typedef struct block { …; struct block *next; … } block;`. Both work. They're basically equivalent. — Jonathan Leffler, Mar 22 '16 at 06:51

score 0 · Accepted Answer · answered Mar 22 '16 at 06:51

0

Forward declare first ie

typedef struct block block;

then declare the struct ie

struct block {
  bool free;
  block * prev;
  block * next;
  char block_part[];
};

answered Mar 22 '16 at 06:51

Harry

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Is this a valid way of defining a struct that references a node of the same type?

1 Answers1