Pointer points to struct pointer

Hi,

I made a program which can be compiled but not built and run.

The VC++ compiler said that it has unresolved external error.

Here is my code:

#include <stdio.h>

//pointer has pointers

void main()
{
struct int_pointers
{
int *ptr1, *ptr2;
};

struct int_pointers *point, ptrs; //create 2 objects.

point = &ptrs;

int i1 = 123, i2 = 87, i3 = 45;

*(*point).ptr1 = 12; //dereference point and use dot notation

point->ptr2 = &i2; //pointer points pointer

printf("i1 = %d, point->ptr1 = %d\n", i1, *(*point).ptr1); //12

printf("i2 = %d, point->ptr2 = %d\n", i2, *point->ptr2); //87

}

Anyone knows why?

Thanks

gogo

I am not sure what the 'unresolved external error' is from. The compiler should list a specific name for the error. Could be that you are missing a library file. Maybe try changing your main() to return an int value.

Code:

---

int main()
{
    /* ..... code ....*/
    return 0;
}

---

Also, your program may compile but it is not going to run anyway. You are attempting to assign a constant value to a dereferenced pointer that has not been assigned any memory. You will have to change you code to look something like this:

Code:

---

#include <stdio.h>
#include <malloc.h>

//pointer has pointers

int main()
{
    struct int_pointers
    {
        int *ptr1, *ptr2;
    };

    struct int_pointers *point, ptrs; //create 2 objects.

    point = &ptrs;

    int i1 = 123, i2 = 87, i3 = 45;

    (*point).ptr1 = (int *)malloc(sizeof(int));
    *(*point).ptr1 = 12; //dereference point and use dot notation

    point->ptr2 = &i2; //pointer points pointer

    printf("i1 = %d, point->ptr1 = %d\n", i1, *(*point).ptr1); //12

    printf("i2 = %d, point->ptr2 = %d\n", i2, *point->ptr2); //87

    free ((*point).ptr1);

    return 0;
}

---

David

I don't think it is related to the malloc issue as (1) I can run this code one mth ago, (2) It shows the same errors even I added (*point).ptr1 = (int *)malloc(sizeof(int));.

To be more specific, the errors are:

Linking...
LIBCD.lib(wincrt0.obj) : error LNK2001: unresolved external symbol _WinMain@16
Debug/ex.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

ex.exe - 2 error(s), 0 warning(s)

I used VC++ compiler and run on win2k prof.

Any idea?

Thanks a lot for your help.

gogo

Quote:

---

LIBCD.lib(wincrt0.obj) : error LNK2001: unresolved external symbol _WinMain@16

---

This means that the compiler is looking for the WinMain() function which is the driver for Windows-based applications, i.e. you are trying to build a Win32 Application (Windows). You need to change to a Win32 Console Application.
The best thing to try is to create a new Win32 Console Application and add your existing .cpp file to the new project. This should clear it up.

David

Thanks and it works now.

gogo