The dumpbin utility gives a different result if I include a path

Question

Investigating the bit width of DLLs on my Windows 10/64 bit box with Visual Studiop 2013 installed.

dumpbin /headers C:\windows\system32\msvcp120.dll | findstr machine

reports: 8664 machine (x64)

but

cd C:\windows\system32\
dumpbin /headers .\msvcp120.dll | findstr machine

reports: 14C machine (x86) 32 bit word machine

I've tried it on several machines with the same result. What's going on ?

Thanks Hans - that makes sense. I think I am using the 32 bit version of dumpbin since I use the "x86 Native Tools Command Prompt" to run the commands. If I explicitly use the 64 bit version ("C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\amd64\dumpbin.exe") it correctly reports 64 bit for the \windows\system32 one and 32 bit for the \windows\syswon64 one irrespective of where I run it from. — speedwell, Apr 25 '17 at 21:04

score 2 · Accepted Answer · answered Apr 25 '17 at 21:15

This is the file system redirector at work, always active on a 64-bit OS when you look at the c:\windows\system32 directory. You are actually looking at c:\windows\syswow64\msvcp120.dll, thus the machine type is x86. Caused primarily by running the 32-bit version of dumpbin.exe, like most users would. Only the 64-bit version (vc/bin/amd64 directory) does not get redirected.

I was puzzled a bit and discovered one aspect of the redirector I did not know before. It redirects only relative paths. So .\msvcp120.dll or ..\system32\msvcp120.dll. But not a full path, like c:\windows\system32\msvcp120.dll. Drive letter is not actually important.

The dumpbin utility gives a different result if I include a path

1 Answers1