Closure mechanism implementation in pure C

closures.c

#include <stdlib.h>

typedef struct {
    int someInt;
    char* someString; // and other captured objects
} Captures;

int addingStuff(Captures* captures, int param) {
    return captures->someInt + param;
}

typedef struct {
    Captures* captures;
    int (*lambda)(Captures* captures, int param);
} Closure;

void usage() {
    Closure* closure = malloc(sizeof(Closure));
    closure->captures = malloc(sizeof(Captures));
    closure->captures->someInt = 3;
    closure->lambda = addingStuff;
    
    int res = closure->lambda(closure->captures, 35); // 35 + 3 = 38
}