boost::interprocess::shared_memory_object::remove fails - dll

I made some test and I was able to create and remove boost::interprocess::shared_memory_object in a C++/CLI executable without problems. In a C++/CLI dll plugin I'm only able to create the boost::interprocess::shared_memory_object but the removal fails. I verified that the file exists at the time of removal - it is present in boost::interprocess folder in a subfolder named "20110606204418.125000". The memory hasn't been mapped by any other process. Any ideas what might be the cause? At the beginning I thought it may have something to do with the project being a dll and targeting CLR but honestly I don't know.
EDIT: the removal code is called by a different thread than the creation code - is this disallowed?

During debugging I noticed that the file path that is to be removed inside boost::interprocess::shared_memory_object::remove is different from the file created by boost::interprocess::shared_memory_object constructor - the path to be removed points at the root of "boost_interprocess" folder while the actually created file is in the "boost_interprocess/20110606204418.125000" folder. So I reported a bug to boost. We will see what they do about it.

Related

Minimum of MyProject Files needed

I am writing a very basic library in VB.NET
The library just contains classes and modules.
Now in built output I see this files
Application.Designer.vb
Application.myapp
AssemblyInfo.vb
Resources.Designer.vb
Resources.resx
Settings.Designer.vb
Settings.settings
Since I've seen other libraries with only AssemblyInfo.vb file, I was wondering if I can delete the rest.
What is the minimum of files I need here for the lib to work correctly, since I don't have any ressource or setting?
All the files you listed are necessary for a vb.net library project. And these files are generated (in My Project folder) when the project created not the build output files. So you need to keep all the files you listed in order to develop and build your project locally.
And for the files of build output, you can add these files in .gitignore.
When you create a project in VS, you select a predefined template that dictates what gets created. People often become accustomed to seeing the superfluous objects that a given template creates and assume that those objects are mandatory and must be there, However, much of it is not needed.
There is also the Empty Project template (the exact name of this template varies depending on the VS version used).
In VS2017, selection of the template would look like this:
This is a bare-bones project and the Solution Explorer will look like this:
As you can see, there are no pre-loaded references. You will need to add them yourself. About the only thing defined in this template is that you are using the VB language; This project starts out as a WinForm type, so go to the Project Properties->Application tab and change the "Application type" to "Class Library" since you want to create a library.
You may find it useful to start with an Empty Project and add the stuff you normally use and then export the project as new template (in VS2017: Project Menu->Export Template). For more on creating termplates, see: Creating Project and Item Templates
Edit: I just realized that I did not answer your real question about deleting the unused items. I just did a test case and deleted the items under MyProject. I received an error on deletion, but doing a clean/rebuild allowed me to proceed without issues. I would recommend that you backup the project before attempting this on an existing project, but I saw no long term issues in deleting unneeded objects from MyProject.

What is the most easy and fast way to edit PE executable file to make it load specified DLL at startup?

I need to make some exe file to load my DLL at startup...
What is the easiest way to do it?
I need this exactly, no any injectors or starters.
I though about adding one more code section into exe, rewriting to there entry point logic and placing DLL loading code, then NOPing original entry point and calling my custom made entry point function. Will this work?
Are there any other easer ways?
I also thinking about changing one of system dll name in hex editor to name of my DLL. Will this work? If my dll then load that replaced system dll?
Any thoughts?
Adding it to the PE's import table should be enough. Woodman's lists a few tools which can do it:
http://www.woodmann.com/collaborative/tools/index.php/Category:Import_Editors

MVC - Application Assembly

Question:
If I have multiple projects in one solution is it still considered a single assembly?
Background Information:
I'm aware the 'MyApplication/Properties/AssemblyInfo.cs' file exists. Further, I confirmed that when I:
Add a project to the solution.
Appropriately reference the newly added project.
Lastly, Build the solution.
The 'MyApplication/Properties/AssemblyInfo.cs' file has not changed. This leaves me to believe, and please correct me if I'm wrong that I'll have met the demand.
Thank you
No.
Each project is compiled into one assembly in your case. The assemblyinfo.cs file (for each project) should not change at all when you compile anything. Also, that file's name is not important at all; it's the global attributes inside it that cause various properties of the assembly being created to be set. That file's name and location are simply a convention.

VB.Net embedded Flash Object creates problems

Ì have had this problem in a number of projects and I have almost given up. I am sure there is a solution though. When I insert a Flash object in a VB.Net Windows Forms application, it works fine for a little while and then I see this error in the Design Screen. I am using Visual Studio 2010
Could not load file or assembly 'Interop.ShockwaveFlashObjects, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.
I have read several descriptions of why this happens, and apparently it has something to do with strong naming (or lack thereof), but have not found a solution yet. I used Add Reference->COM->Shockwave Flash (C:\Windows\SysWOW64\Macromed\Flash\Flash32_11_2_202_235.ocx) If I ignore the error it appears to work fine, but I don't want my users to have a problem.
I know I can use a browser control and play the Flash in that, but for reasons I won't get into, I have to use a Flash control. Any ideas would help.
Okay. I can't promise this to work for you, but it worked for me.
First, you have to locate a file on your computer titled AxImp.exe. You have to run it from the command prompt. This file is located (for me at least) here:
C:\Program Files\Microsoft SDKs\Windows\v7.0\Bin\x64
Once you do find and run it, you have to point it to the correct Flash.ocx file you're using, like so:
AxImp.exe <path>\Flash.ocx
Once you've done that you should end up with 2 DLL files in the same directory as the .ocx file. One called AxShockwaveFlashObjects.dll and another called ShockwaveFlashObjects.dll.
You don't care about ShockwaveFlashObjects.dll, just AxShockwaveFlashObjects.dll.
Grab that file and the Flash*.ocx file and paste them into the project directory.
Then include them into your references. This should open up two new references, AxShockwaveObjects and ShockwaveObjects.
Make sure you're Using both of them.
After this, you have to register the Flash*.ocx using RegSvr32 from your command prompt (make sure to run CMD in admin mode). That is done like so:
C:\RegSvr32 <path>\Flash.ocx
This worked for me. I was having the exact same problem (which is what led me here). It could be a half backed hack workaround but for now, that's how it worked for me.
Let me know if it works for you or not.
Hope it goes well for you.
I know this is an old post but I had this issue yesterday and the solution, at least in my case, was very simple. All I had to do was to change the Platform and Platform Target to x86 (Build tab of project property).

add custom DLL search path # application startup

I'm racking my brain trying to come up with an elegant solution to a DLL load problem. I have an application that statically links to other lib files which load DLLs. I'm not loading the DLLs directly. I'd like to have some DLLs in another folder other than the folder that the executable is in. Something like %working_folder%\dlls - I'd rather not have dozens (yes ... dozens) of DLLs in my %working_folder%.
I'm trying to develop something that is part of the main app that will adjust the search path # startup. The problem I'm running into is that this new custom DLL path isn't in the system search path. When I start the app it crashes (STATUS_DLL_NOT_FOUND) because the necessary DLLs are not in the appropriate places. What I'd like to do is to check # startup if this new custom DLL folder is in the process environment variable search path and if not add it. Problem is, the application attempts to load all these DLLs before the app executes one line of code.
How do I fix this? I've considered writing a help app that starts first, adjusts the environment variables appropriately and the launches the main app via CreateProcess. This will work I'm sure of it but it makes things difficult on the developers. When they debug the main app they're not going to launch a helper app first - not that they could even do that.
I've tried the registry app path feature with no success. Same chicken and egg problem as before.
What can I do here?
I found Matthew's answer worked for me.
In visual studio 2012 goto your project properties and in
Configuration Properties->Linker->Input->Delay Loaded Dlls
add each dll file that you want to not load until needed.
Although it no longer needs to run before main, this is my code to set the new search path
class RunBeforeMain
{
public:
RunBeforeMain()
{
const TCHAR* dllPathEnvName= name of env variable to directory containing dlls
const TCHAR* pathEnvName= TEXT("Path");
TCHAR newSearchPath[4096];
::GetEnvironmentVariable(dllPathEnvName, newSearchPath, MAX_PATH);
//append bin
_tcscat_s(newSearchPath, MAX_PATH, TEXT("bin;"));
size_t length = _tcslen(newSearchPath);
//append existing Path
::GetEnvironmentVariable(pathEnvName, newSearchPath + length, 4096-length);
::SetEnvironmentVariable(pathEnvName, newSearchPath);
}
};
static RunBeforeMain runBeforeMain; //constructor code will run before main.
[Edit - after re-reading the question I see that the problem you're having is that the DLLs are getting loaded before main starts]
I'm guessing that those libraries are written in C++ and are loading the DLLs from the constructor of some objects in global scope. This is problematic. Allow me to quote Yossi Kreinin:
Do it first thing in main(). If you use C++, you should do it first thing before main(), because people can use FP in constructors of global variables. This can be achieved by figuring out the compiler-specific translation unit initialization order, compiling your own C/C++ start-up library, overriding the entry point of a compiled start-up library using stuff like LD_PRELOAD, overwriting it in a statically linked program right there in the binary image, having a coding convention forcing to call FloatingPointSingleton::instance() before using FP, or shooting the people who like to do things before main(). It’s a trade-off.
[Original answer below]
See this page for the search algorithm used for loading DLLs. You can use SetDllDirectory() to add a directory to the DLL search path.
You also should be able to add a directory to the PATH environment variable using GetEnvironmentVariable() and SetEnvironmentVariable().
Another option is to change the current working directory to the folder containing the DLLs with SetCurrentDirectory(). Just make sure to change the working directory back after loading the DLLs if you ever load any files using relative filenames.
My recommendation is to use delayload linking for the DLLs and call SetDllDirectory() early enough so it can find them when the methods/functions are invoked.