int pointer as argument in function valgrind error Invalid read of size 4

What is wrong in this simple code? It works, but valgrind shows errors. How should it look like?

What should be definition of int func(int*)?

main.cpp:

#include <iostream>
#include <stdio.h>
#include <cstdlib>

using namespace std;

int func(int* terminal);

int main()
{
    int* x = (int*)malloc(3);
    x[0]=1;
    x[1]=2;
    x[2]=3;

    func(x);

}

int func(int *terminal)
{
    cout<<(*terminal)<<endl;
    cout<<(*terminal+1)<<endl;
    cout<<(*terminal+2)<<endl;

    return 1;
}

valgrind log:

==2806== Invalid write of size 4
==2806==    at 0x80486A6: main (main.cpp:12)
==2806==  Address 0x434f028 is 0 bytes inside a block of size 3 alloc'd
==2806==    at 0x402A17C: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==2806==    by 0x804869D: main (main.cpp:11)
==2806== 
==2806== Invalid write of size 4
==2806==    at 0x80486B3: main (main.cpp:13)
==2806==  Address 0x434f02c is 1 bytes after a block of size 3 alloc'd
==2806==    at 0x402A17C: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==2806==    by 0x804869D: main (main.cpp:11)
==2806== 
==2806== Invalid write of size 4
==2806==    at 0x80486C0: main (main.cpp:14)
==2806==  Address 0x434f030 is 5 bytes after a block of size 3 alloc'd
==2806==    at 0x402A17C: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==2806==    by 0x804869D: main (main.cpp:11)
==2806== 
==2806== Invalid read of size 4
==2806==    at 0x80486F1: func(int*) (main.cpp:22)
==2806==    by 0x80486D1: main (main.cpp:16)
==2806==  Address 0x434f028 is 0 bytes inside a block of size 3 alloc'd
==2806==    at 0x402A17C: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==2806==    by 0x804869D: main (main.cpp:11)
==2806== 
1
==2806== Invalid read of size 4
==2806==    at 0x804871A: func(int*) (main.cpp:23)
==2806==    by 0x80486D1: main (main.cpp:16)
==2806==  Address 0x434f028 is 0 bytes inside a block of size 3 alloc'd
==2806==    at 0x402A17C: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==2806==    by 0x804869D: main (main.cpp:11)
==2806== 
2
==2806== Invalid read of size 4
==2806==    at 0x8048746: func(int*) (main.cpp:24)
==2806==    by 0x80486D1: main (main.cpp:16)
==2806==  Address 0x434f028 is 0 bytes inside a block of size 3 alloc'd
==2806==    at 0x402A17C: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==2806==    by 0x804869D: main (main.cpp:11)
==2806== 

Maybe I should go fishing instead of studying c++.

via Chebli Mohamed