How to import a DLL into a Microsoft Visual Studio Fortran Project?

Hello,

I am having problems importing a DLL into my current Fortran project. The DLL file I am trying to import, fdlltest.dll, has the following functions defined when I do dumpbin /exports:

C:\temp>dumpbin /exports fdlltest.dll
Microsoft (R) COFF/PE Dumper Version 12.00.40629.0
Copyright (C) Microsoft Corporation.  All rights reserved.


Dump of file fdlltest.dll

File Type: DLL

  Section contains the following exports for fdlltest.dll

    00000000 characteristics
    560ED478 time date stamp Fri Oct 02 14:01:12 2015
        0.00 version
           1 ordinal base
           3 number of functions
           3 number of names

    ordinal hint RVA      name

          1    0 00001000 add2i
          2    1 00001010 add2r
          3    2 00001040 simpson

  Summary

        1000 .data
        1000 .rdata
        1000 .reloc
        1000 .rsrc
        1000 .text

Next, I need to know step-by-step how to import the add2i, add2r, and simpson functions from this DLL located in C:\temp into my current Fortran project. I do not want examples with *.lib, since the actual DLL I want to use once I get past this example does not have a companion *.lib. This is my Fortran code which is supposed to generate an EXE that is linked to the DLL file:

program fdllrun
 implicit none
INTERFACE
 INTEGER FUNCTION add2i(a,b)
!DEC$ ATTRIBUTES DLLIMPORT, ALIAS:"add2i" :: add2i
!DEC$ ATTRIBUTES REFERENCE::a, b
  INTEGER, intent(in), value:: a, b
 END FUNCTION add2i
 
 REAL FUNCTION add2r(a,b)
!DEC$ ATTRIBUTES DLLIMPORT, ALIAS:"add2r" :: add2r
!DEC$ ATTRIBUTES REFERENCE::a, b
  REAL, intent(in), value:: a, b
 END FUNCTION add2r

 REAL FUNCTION simpson(f, a, b, n)
!DEC$ ATTRIBUTES DLLIMPORT, ALIAS:"simpson" :: simpson
!DEC$ ATTRIBUTES REFERENCE::f, a, b, n
  EXTERNAL f
  real, intent(in), value ::  a, b
  integer, intent(in), value :: n
 END FUNCTION simpson
END INTERFACE

 ! Variables
 INTEGER :: i1, i2, ians
 i1=1
 i2=2

 ! Body of fdllrun
 ians = add2i(i1, i2)
 print '(I3)', ians

end program fdllrun

I tried to right click on my project and do Add -> Existing Item, then browse to the DLL file located in C:\temp, then Build All. It does not work. The errors I get when I try to compile are:

Error 1  error LNK2019: unresolved external symbol __imp_add2i referenced in function _MAIN__ fdllrun.obj 
Error 2  fatal error LNK1120: 1 unresolved externals Release\fdllrun.exe