If you have no idea what “cursed” is, well, this is it.
As we all know, C not Objekt Orientiert is. tbh, I don’t like inheritence at
all. But perhaps when maintaining some old codebase, you want to expand a struct
without messing with the existing definitions.
Cursed but works
The old struct
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typedef struct _base{
int old_member1;
int old_member2;
int old_member3;
}base_t;
base_t init_base(){
// do something, maybe
base_t b = {
.old_member1 = 0,
.old_member2 = 0,
.old_member3 = 0,
};
return b;
}
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Now extend it into a new struct: Make sure the base struct is the first member
of extended struct, so that you can cast them into each other…
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typedef struct _extended {
base_t base;
int new_member4;
int new_member5;
int new_member6;
} extended_t;
extended_t init_extended(){
extended_t e = {
.base = init_base(),
.new_member4 = 0,
.new_member5 = 0,
.new_member6 = 0,
};
return e;
}
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and you can safely(?) cast them:
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int main(){
extended_t e = init_extended();
base_t* bp = (base_t*)(&e);
return 0;
}
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