Resolve circular typedef dependency?

user_30470 0
Viewed 21590

What is the best way to resolve the following circular dependency in typedef-ing these structs?
Note the C language tag - I'm looking for a solution in standard gcc C.

typedef struct {
    char* name;
    int age;
    int lefthanded;
    People* friends;
} Person;

typedef struct {
    int count;
    int max;
    Person* data;
} People;
circular-dependency c
6 Answers

Forward-declare one of the structs:


struct people;

typedef struct {
  /* same as before */
  struct people* friends;
} Person;

typedef struct people {
  /* same as before */
} People;
user_1066710

As for readability :

typedef struct Foo_ Foo;
typedef struct Bar_ Bar;

struct Foo_ {
    Bar *bar;
};

struct Bar_ {
    Foo *foo;
};

It might be a good idea to avoid typedef struct altogether;

user_1081720

Since Person just wants a pointer to People, it should be fine to just predeclare the latter:

typedef struct People People;

Then change the second declaration to just declare using the struct tag, like so:

struct People {
    int count;
    int max;
    Person data[];
};
unwind_281690 
struct _People;

typedef struct {
    char* name;
    int age;
    int lefthanded;
    struct _People* friends;
} Person;

struct _People {
    int count;
    int max;
    Person data[1];
};

Note: Is Person data[]; standard?

Serge_123790 
struct People_struct;

typedef struct {
    char* name;
    int age;
    int lefthanded;
    struct People_struct* friends;
} Person;

typedef struct People_struct {
    int count;
    int max;
    Person data[];
} People;
user_1087190
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