Realloc, malloc

[Tomhet]

Why there is memory leak when I use realloc, malloc alot and that sure those res going to be freed?

I noticed it happens too with std::vector, deque etc containers

#include<stdio.h>

#include<windows.h>

/**************************************************************************************************/

#include<stddef.h>
#include<stdlib.h>

static const size_t VOID_SIZE=sizeof(void*);

typedef struct{
    void**list;
    size_t len;
    size_t cap;
}voids;

voids*voidsnew(size_t cap){
    voids*cont=(voids*)malloc(sizeof(voids));
        cont->len=0;
        cont->cap=cap;
        cont->list=(void**)malloc(VOID_SIZE*cap);
    return cont;
};

void voidsclose(voids*cont){
    free(cont->list);
    free(cont);
};

void voidspush(voids*cont,void*item){
    if(cont->len==cont->cap){
        cont->cap+=cont->cap;
        cont->list=realloc(cont->list,VOID_SIZE*cont->cap);
    };

    cont->list[cont->len]=item;
    ++cont->len;
};

void voidspop(voids*cont){
    --cont->len;
    cont->list[cont->len]=NULL;
};

/**************************************************************************************************/

int main(){
    size_t pos=0;
    size_t len=10000000;

    //voids*ar=voidsnew(len);//with this memory will be around 300-400 kB after free-ing
    voids*ar=voidsnew(4);  //with this memory will be around 800-900 kB after free-ing

    for(;pos<len;++pos){
        voidspush(ar,(void*)pos);
    };

    Sleep(2000);

    voidsclose(ar);

    getchar();
    return 0;
}