C: pointer to struct in the struct definition


How can I have a pointer to the next struct in the definition of this struct:

typedef struct A {
  int a;
  int b;
  A*  next;
} A;

this is how I first wrote it but it does not work.

Best Answer

You can define the typedef and forward declare the struct first in one statement, and then define the struct in a subsequent definition.

typedef struct A A;

struct A
    int a;
    int b;
    A* next;

Edit: As others have mentioned, without the forward declaration the struct name is still valid inside the struct definition (i.e. you can used struct A), but the typedef is not available until after the typedef definition is complete (so using just A wouldn't be valid). This may not matter too much with just one pointer member, but if you have a complex data structure with lots of self-type pointers, may be less wieldy.