How to call upon a .dll file from C++ and extract the functions of it? - dll

Question

I would like to know the proper procedure for calling a .dll file with also having a .cpp and .h files for a certain application. I have a program which is the .cpp file with different .h header files and I also included the .dll file into the folder where the .cpp and .h files are located. I would like to know in the .cpp code how am I able to call upon this .dll file since inside of it there are different functions that will allow a DDC264 Evaluation Board to read data from memory through usb and extract the data. I am using a program called DevC++ and I am receiving a current Error which is [Id] returned 1 exit status and MakefileWin has changed.
Attached below is a snippit of the .cpp code:
I also would like to know how to fix both of these errors .enter image description hereenter image description here
// USB_IO_for_VB6.cpp : Defines the entry point for the DLL application.
//
#include "stdafx.h"
#include "USB_IO_For_VB6.h"
#include "CyAPI.h"
#include <cstring>
#include <malloc.h>
#include "BASETSD.H"
#include <math.h>
#include <stdio.h>
// #include <string.h>
BOOL APIENTRY DllMain( HANDLE hModule,
DWORD ul_reason_for_call,
LPVOID lpReserved
)
{
switch (ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
case DLL_THREAD_ATTACH:
case DLL_THREAD_DETACH:
case DLL_PROCESS_DETACH:
break;
}
return TRUE;
}
// This is an example of an exported variable
//int USB_IO_FOR_VB6_EXPORTS int USB_IO_for_VB6_API =22;
I
USB_IO_FOR_VB6_API int nUSB_IO_for_VB6 = 22;
#define STRINGLEN 65536 //the larger this number is, the faster the data is shifted in.
#define MAX_CHANNELS_FAST 4096 // 2048= 1024A + 1024B
#define DBP 0 //debug print - 1 enables writing some information to a file in "C:\temp\"
// This function reads the device descriptors from the Cypress USB Chip(s).
// It returns arrays of values, one set of values per device detected.
// The user can then use the visual basic software to select which device to use.
int __stdcall ReadDeviceDescriptors(int *USBdevCount, int *bLengthPass, int *bDescriptorTypePass,
long *bcdUSBPass, int *bDeviceClassPass, int *bDeviceSubClassPass,
int *bDeviceProtocolPass, int *bMaxPacketSize0Pass, long *idVendorPass,
long *idProductPass, long *bcdDevicePass, int *iManufacturerPass,
int *iProductPass, int *iSerialNumberPass, int *bNumConfigurationsPass)
{
CCyUSBDevice *USBDevice;
USB_DEVICE_DESCRIPTOR descr;
USBDevice = new CCyUSBDevice(NULL); // Create an instance of CCyUSBDevice
USBdevCount[0] = USBDevice->DeviceCount();
for (int i=0; i < USBDevice->DeviceCount(); i++)
{
if (USBDevice->Open(i))
{
USBDevice->GetDeviceDescriptor(&descr);
bLengthPass[i]=descr.bLength;
bDescriptorTypePass[i]=descr.bDescriptorType;
bcdUSBPass[i]=descr.bcdUSB;
bDeviceClassPass[i]=descr.bDeviceClass;
bDeviceSubClassPass[i]=descr.bDeviceSubClass;
bDeviceProtocolPass[i]=descr.bDeviceProtocol;
bMaxPacketSize0Pass[i]=descr.bMaxPacketSize0;
idVendorPass[i]=descr.idVendor;
idProductPass[i]=descr.idProduct;
bcdDevicePass[i]=descr.bcdDevice;
iManufacturerPass[i]=descr.iManufacturer;
iProductPass[i]=descr.iProduct;
iSerialNumberPass[i]=descr.iSerialNumber;
bNumConfigurationsPass[i]=descr.bNumConfigurations;
USBDevice->Close();
}
}
return( USBdevCount[0] );
}
I am not sure about how to go about calling a .dll file in C++, I am fairly new to Object Oriented programming.
Regarding the MakefileWin error I tried changing the TDM-GCC release version from 32 to 64 bits and the error continues.
I also tried deleting the dllmain.cpp which is another cpp file that is not needed and moving another original.cpp file from the folder that is shown in one of the images.
I only have a single .cpp file running on my DevC++ compiler which I thought would not cause the Error [Id] returned 1 to exit status to pop up.