# Loading a shared library on Windows
**URL:** https://discourse.julialang.org/t/loading-a-shared-library-on-windows/10346
**Category:** General Usage
**Created:** [April 14, 2018, 10:05pm UTC](https://discourse.julialang.org/t/loading-a-shared-library-on-windows/10346 "2018-04-14T22:05:15Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 14, 2018, 10:05pm UTC](https://discourse.julialang.org/t/loading-a-shared-library-on-windows/10346/1 "2018-04-14T22:05:15Z")
I built a shared library, according to the MSVC property manager it is a 32-bit DLL. Yet, when I do
```julia
julia> lib = Libdl.dlopen("C:\\Users\\PetrKrysl\\Documents\\Work-in-progress\\H2Lib-community\\build\\Library\\Release\\H2LIB.dll")
```
I get
```julia
ERROR: could not load library "C:\Users\PetrKrysl\Documents\Work-in-progress\H2Lib-community\build\Library\Release\H2LIB.dll"
%1 is not a valid Win32 application.
```
How do I begin to figure out what is wrong with that DLL?
---
### Author:  [@Crghilardi](https://discourse.julialang.org/u/Crghilardi)
#### Post date: [April 14, 2018, 11:07pm UTC](https://discourse.julialang.org/t/loading-a-shared-library-on-windows/10346/2 "2018-04-14T23:07:21Z")
[There was a similar thread](https://discourse.julialang.org/t/problems-calling-fortran-in-windows/10271) recently where 32 vs 64 bit windows/Julia was an issue that may be a starting point. Can you give any more info on your build process?
---
### Author:  [@Ronis\_BR](https://discourse.julialang.org/u/Ronis_BR)
#### Post date: [April 15, 2018, 2:10pm UTC](https://discourse.julialang.org/t/loading-a-shared-library-on-windows/10346/3 "2018-04-15T14:10:54Z")
My student, who solved the problem, will write a tutorial to the others students showing how he did it. As soon as he finishes, I will post the steps here!
---
### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 19, 2018, 1:48am UTC](https://discourse.julialang.org/t/loading-a-shared-library-on-windows/10346/4 "2018-04-19T01:48:12Z")
So, is the issue that a 64-bit Julia cannot load a 32-bit shared library?
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### Author:  [@helgee](https://discourse.julialang.org/u/helgee)
#### Post date: [April 19, 2018, 12:28pm UTC](https://discourse.julialang.org/t/loading-a-shared-library-on-windows/10346/5 "2018-04-19T12:28:04Z")
Yes.
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### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 19, 2018, 5:24pm UTC](https://discourse.julialang.org/t/loading-a-shared-library-on-windows/10346/6 "2018-04-19T17:24:34Z")
Thanks! Is that a general statement for any operating system? Clearly I can run 32-bit Julia on a 64-bit Windows 10… So isn’t that exe loading some Windows libs?
---
### Author:  [@joa-quim](https://discourse.julialang.org/u/joa-quim)
#### Post date: [April 19, 2018, 11:12pm UTC](https://discourse.julialang.org/t/loading-a-shared-library-on-windows/10346/7 "2018-04-19T23:12:24Z")
> [@PetrKryslUCSD](#):
>
> So isn’t that exe loading some Windows libs?
Yes, those in WOW (Windows On Windows), which is the Windows64 subsystem for 32 bits.
---
### Author:  [@PetrKryslUCSD](https://discourse.julialang.org/u/PetrKryslUCSD)
#### Post date: [April 20, 2018, 3:05am UTC](https://discourse.julialang.org/t/loading-a-shared-library-on-windows/10346/8 "2018-04-20T03:05:40Z")
Got it. Thanks.