exporting function with parm pointer to char string

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From: Angel (none)
Date: 03/02/04 

Date: Tue, 2 Mar 2004 18:25:24 -0400

I'm exporting a C-style function call with this syntax:

int getDate(char *date);

I'm trying to export to my c# app like this:

[DllImport("C:\\zm7\\Developm\\DLL\\W32.DLL")]
public static extern int getDate(System.IntPtr ptr);
public void getDate()
{
    IntPtr ptr = new IntPtr();
    string str = "";
    getDate(ptr); //// ERROR: Object reference not set to an instance of
an object
    str = Marshal.PtrToStringAnsi(ptr);
}

What Am I doing wrong?

Thanks.

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