-----------------------MYSTRUCT.H---------------------------
#ifndef _MYSTRUCT_H_
#define _MYSTRUCT_H_

typedef struct MyStruct {
    int myValue1;
    char myValue2;
    void (*setValue1)(struct MyStruct *myStruct, int myValue1);
    void (*setValue2)(struct MyStruct *myStruct, char myValue2);
} MyStruct;

struct MyStruct myStructConstructor();
void setValue1(struct MyStruct *myStruct, int myValue1);
void setValue2(struct MyStruct *myStruct, char myValue2);


#endif

--------------------------MYSTRUCT.C-------------------------
#include "MyStruct.h"
#include <stdio.h>

struct MyStruct myStructConstructor() {
    MyStruct myStruct;

    myStruct.setValue1 = setValue1;
    myStruct.setValue2 = setValue2;
}

void setValue1(struct MyStruct *myStruct, int myValue1) {
    myStruct->myValue1 = myValue1;
}

void setValue2(struct MyStruct *myStruct, char myValue2) {
    myStruct->myValue2 = myValue2;
}

int main(void) {
    MyStruct str = myStructConstructor();

    str.setValue1(&str, 1);

    printf("%d\n", str.myValue1);

    return 0;
}