IOException: Sharing violation on path "..\plctag.dll"

[the-pied-shadow]

Hello. I'm attempting to run code very similar to your example.cs to read and write to a boolean tag. However, when it is run I get this error: "IOException: Sharing violation on path C:\Users<user>\Desktop<project>\Assets\Plugins\plctag.dll"

I've been unable to understand the issue anymore through research.

Here is the callstack:

IOException: Sharing violation on path C:\Users\bhilsdon\Desktop\PLC Networking\Assets\Plugins\plctag.dll
System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize, System.Boolean anonymous, System.IO.FileOptions options) (at <9577ac7a62ef43179789031239ba8798>:0)
System.IO.FileStream..ctor (System.String path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share, System.Int32 bufferSize) (at <9577ac7a62ef43179789031239ba8798>:0)
(wrapper remoting-invoke-with-check) System.IO.FileStream..ctor(string,System.IO.FileMode,System.IO.FileAccess,System.IO.FileShare,int)
System.IO.File.Create (System.String path, System.Int32 bufferSize) (at <9577ac7a62ef43179789031239ba8798>:0)
System.IO.File.Create (System.String path) (at <9577ac7a62ef43179789031239ba8798>:0)
System.IO.File.WriteAllBytes (System.String path, System.Byte[] bytes) (at <9577ac7a62ef43179789031239ba8798>:0)
libplctag.NativeImport.LibraryExtractor.ExtractAppropriateLibraryToDirectory (System.String outputDirectory) (at <50abcd0f95e747348b5f7c669256d26d>:0)
libplctag.NativeImport.LibraryExtractor.Init (System.Boolean forceExtract) (at <50abcd0f95e747348b5f7c669256d26d>:0)
libplctag.NativeImport.plctag.ExtractLibraryIfRequired () (at <50abcd0f95e747348b5f7c669256d26d>:0)
libplctag.NativeImport.plctag.plc_tag_create (System.String lpString, System.Int32 timeout) (at <50abcd0f95e747348b5f7c669256d26d>:0)
libplctag.NativeTag.plc_tag_create (System.String lpString, System.Int32 timeout) (at <18439e085ec54e2891bd246d29cef40d>:0)
libplctag.NativeTagWrapper.Initialize () (at <18439e085ec54e2891bd246d29cef40d>:0)
libplctag.Tag.Initialize () (at <18439e085ec54e2891bd246d29cef40d>:0)
libplctag.Tag`2[M,T].Initialize () (at <18439e085ec54e2891bd246d29cef40d>:0)

As mentioned above my code is very similar to example.cs. The variables used below are set elsewhere.

        Tag<BoolPlcMapper, bool> mytag = new Tag<BoolPlcMapper, bool>()
        {
            Name = TagName,
            Gateway = GatewayIPAddress,
            Path = path,    
            PlcType = plc,
            Protocol = protocol,
            Timeout = TimeSpan.FromSeconds(5)
        };

        mytag.Initialize();
        mytag.Value = true;
        mytag.Write();
        mytag.Read();
        Debug.Log(mytag.Value);

The notable outlying factor here is I'm attempting to use in Unity Engine.

Thank you for this tool and your help.

[the-pied-shadow]

Upon some further investigation I've realized that what first happens is I get an "EntryPointNotFound" exception. After this exception is thrown and the program is run again, I get the sharing violation instead. This process can be reproduced when I delete the plctag.dll. So the original issue may just be that I have the wrong information for the tag.

[jkoplo]

You may realize this (or have figured it out) but in order to support multiple platforms, we extract the proper base libplctag DLL to a directory before importing it and wrapping those calls in our C# library. There's more information about this in main Readme.

What it looks like is that you might have a Windows permission issue based on where it's extracting and how your app is running. That might be caused by your initial error or not...

[the-pied-shadow]

I appreciate the reply. I'm afraid I'm not well experienced with PLCs or Ethernet/IP communication and I understand if you don't have time to explain things that aren't related to your package.

When I get the error:
EntryPointNotFoundException: plc_tag_create

Am I correct in interpreting this as it failing to connect to the PLC or could this be that it did connect and didn't find the tag I specified?

[timyhac]

No, this issue is all related to the inability of the NativeImport to extract the appropriate libplctag core library properly.

That error is saying that PInvoke can't find the C function in the native dll.

To get around this issue, get a copy of the appropriate plctag.dll and configure ForceExtract to false.
Reading this will help:
https://github.com/libplctag/libplctag.NET#libplctagnativeimport

My guess is that an Antivirus program caused this by locking the file or something.

[the-pied-shadow]

Okay thank you that does bring some clarity for me. Could you point me in the right direction for getting a copy of the appropriate plctag.dll?

[timyhac]

You can download them from the libplctag releases page
https://github.com/libplctag/libplctag/releases

[timyhac]

In terms of what this project could do to resolve this issue, I believe that #137 is key

[lakerty]

Hi just a quick question has anybody done a visual studio xamarin forms android phone project for CompactLogix plc

[jkoplo]

I don't believe so, but it should be possible (maybe). Can you open a new issue and we can discuss in there?

[timyhac]

Yep it worked last time I checked as long as you follow the README.

[lakerty]

Hi I have read this file a few times my knowledge of c# and xamarin forms are limited as I am just starting to learn these.As I use mainly vb.net and my main strengths are plc programs I am getting lost on readme file. Many thanks Get Outlook for Android<https://aka.ms/AAb9ysg>

…

________________________________ From: timyhac ***@***.***> Sent: Thursday, March 3, 2022 10:00:02 AM To: libplctag/libplctag.NET ***@***.***> Cc: lakerty ***@***.***>; Comment ***@***.***> Subject: Re: [libplctag/libplctag.NET] IOException: Sharing violation on path "..\plctag.dll" (#177) Yep it worked last time I checked as long as you follow the README<https://github.com/libplctag/libplctag.NET#developing-for-systems-with-immutable-application-directories>. — Reply to this email directly, view it on GitHub<#177 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AK72AJIO5GVB3H3GN4YD2K3U6CESFANCNFSM457HEGCA>. Triage notifications on the go with GitHub Mobile for iOS<https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android<https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you commented.Message ID: ***@***.***>