32-bit and 64-bit DLL judgment

How can I tell if a DLL file is 32-bit or 64-bit?

1. A tool that is often used in development to VC Dependency Walker
Open the DLL with Depends.exe, which is 64 bits before the file name is 64 marked.

But this method is not omnipotent, can only be easily judged. A lot of them can't be judged.
For example, under 64-bit system C:\Windows\System32\msvcrt.dll

2. Using the Visual Studio Development Tools command dumpbin
Typically located in the VS installation directory Bin subdirectory, such as
C:\Program Files (x86) \microsoft Visual Studio 10.0\vc\bin\amd64>dumpbin.exe
Use the command dumpbin/headers yourdll.dll |find "Machine"

Machine (x64) indicates that the DLL is 64 bits. Otherwise the x86
The following (pe32+) also indicates that the DLL is 64 bits. Otherwise the PE32

Reference http://bbs.pediy.com/showthread.php?p=1369132

32-bit and 64-bit DLL judgment