Nested struct initialization with structs - c

Question

maybe this is a duplicate but I can't find a proper solution for this problem... and I'm sort of being new to C development, and my problem is that I don't know how to initialized a nested struct, take a look for more info...
So the thing is the following:
// another_struct.h
struct AnotherStruct {
void (*some_function)();
}
extern struct AnotherStruct AnotherStruct;
// yet_another_struct.h
struct YetAnotherStruct {
void (*some_function)();
}
extern struct YetAnotherStruct YetAnotherStruct;
// my_struct.h
struct MyStruct1 {
struct AnotherStruct another;
struct YetAnotherStruct and_yet;
}
extern struct MyStruct1 MyStruct1;
In their respective .C file:
struct AnotherStruct AnotherStruct = {
.some_function = blabla
};
struct YetAnotherStruct YetAnotherStruct = {
.some_function = blablabla
};
// I want the initialization of MyStruct1 to have the struct pointing to the structs
struct MyStruct1 MyStruct1 = { /* ?? */ };
/* I was thinking something like this */
struct MyStruct1 MyStruct1 = {
.another = AnotherStruct,
.and_yet = YetAnotherStruct
};
But the compiler complains xD
So my ultimate goal is to be able access the child structures as:
MyStruct1.another.some_function();
Thanks a lot and sorry if this question is duplicate or is way to noob :)

Answer 1

Why don't you construct them like this (No pointer usage):
/* I was thinking something like this */
struct MyStruct1 MyStruct1 = {
.another = { //.another is your struct, just do construct like normal
.some_function = blabla
},
.and_yet = { //The same here.
.some_function = blablabla
}
};
Usage in your code is:
//Call function
MyStruct1.another.some_function();
Using pointers:
// my_struct.h, add pointers
struct MyStruct1 {
struct AnotherStruct *another; //Added pointers
struct YetAnotherStruct *and_yet; //Here too
}
and then use in your .c
struct AnotherStruct AnotherStruct = {
.some_function = blabla
};
struct YetAnotherStruct YetAnotherStruct = {
.some_function = blablabla
};
/* I was thinking something like this */
struct MyStruct1 MyStruct1 = {
.another = &AnotherStruct, //Added & for address
.and_yet = &YetAnotherStruct //Added & for address
};
And later access to your values like:
//Call your function now
MyStruct1.another->some_function();

Answer 2

#tilz0R not enough rep to comment. A little modification to your answer.
typedef struct {
int a_val;
} A;
typedef struct {
float b_val;
} B;
typedef struct {
A *a;
B *b;
} C;
C c = {
.a = &(A){ .a_val = 1 },
.b = &(B){ .b_val = 1. },
};
As for union thingie, probably it is about Microsoft extension syntax
typedef struct {
A;
B;
} C;
C c;
c.a_val = 1; // valid
Unfortunately this one is a non standard extension, moreover it is doomed to never become one since this was a committee decision to maintain compatibility with C++.
Per #Lundin comment. The following code is indeed possible in modern C:
typedef struct {
struct {
int a_val;
};
struct {
float b_val;
};
} C;
C c;
c.a_val = 1;
However this brings little to no benefit (apart from organizing your code) in case of embedding structures into structures. It is pretty cool than it comes to unions though:
typedef struct {
enum {
TA,
TB
} _;
union {
struct {
int a;
};
struct {
float b;
};
};
} C;
C c = { ._ = TA, .a = 1 };
Used compile line:
gcc -std=c11 -Wall -Wextra -pedantic