#include <stdlib.h>
#include "test.h"
extern "C" __declspec(dllexport) int malloctest();

int malloctest(){
    int check = test();
    return check;
}

#include <stdlib.h>
#ifdef __cplusplus
extern "C" {
#endif
int test();
#ifdef __cplusplus
}
#endif

#include "test.h"
int test(){
    int * array = malloc(42 * sizeof(int));
    free(array);
    return 42;
}

gcc -c malloctest.cpp test.c
gcc -shared -o malloctest.dll malloctest.o test.o

class Program
{

    [DllImport("kernel32", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
    static extern IntPtr GetProcAddress(IntPtr hModule, string procName);

    [DllImport("kernel32", SetLastError = true)]
    static extern IntPtr LoadLibrary(string lpFileName);


    public delegate int test();
    static void Main(string[] args)
    {
        IntPtr pcygwin = LoadLibrary("cygwin1.dll");
        IntPtr pcyginit = GetProcAddress(pcygwin, "cygwin_dll_init");
        Action init = (Action)Marshal.GetDelegateForFunctionPointer(pcyginit, typeof(Action));
        init();

        IntPtr libptr = LoadLibrary("malloctest.dll");
        IntPtr funcptr = GetProcAddress(libptr, "malloctest");
        test malloctest = (test)Marshal.GetDelegateForFunctionPointer(funcptr, typeof(test));
        int check = malloctest(); //hold
        Console.WriteLine(check);
    }
}