Default constructor in C

Question

Is there a way to have some kind of default constructor (like a C++ one) for C user types defined with a structure?

I already have a macro which works like a fast in

Answer 1

Using functions to create and dispose of structures has already been mentioned. But in a comment you mentioned that you wanted a "default constructor" - I think you mean that you want to initialize some (all?) of the struct fields to default values.

This is done in C using some coding convention -- either functions, macros, or a mix. I usually do it something like the following --

struct some_struct {
    int a;
    float b;
};
#define some_struct_DEFAULT { 0, 0.0f}
struct some_struct *some_struct_create(void) {
    struct some_struct *ptr = malloc(sizeof some_struct);
    if(!ptr)
        return ptr;

    *ptr = some_struct_DEFAULT;
    return ptr;
}
// (...)
struct some_struct on_stack = some_struct_DEFAULT;
struct some_struct *on_heap = some_struct_create();