Include DLLs

This guide demonstrates how to include DLL files in a folder and seamlessly integrate them into the Debug or Build folder to generate a working build directory. It is particularly useful when dealing with libraries that require specific DLL files.

The following is based on an (IDE) Visual Studio 2022


List of options:


1. Root Directory Linking (Default):


Located in the same directory as .vcxproj known as Root directory.

Simply add the DLL into your project:

File structure (Root directory):

> Example.dll
> main.cpp
> Application.sln
> Application.vcxproj
> Application.vcxproj.user
> Application.vcxproj.filters

Advantages:

  • Linking is done for the user by the (IDE).
  • Beneficial for small projects, where file management is not required.
  • The user does not have to worry about the (IDE) locating them, as long as they are listed within the root directory of the project.

Cons:

  • Directory gets cluttered and harder to manage as the project grows in size.
  • Clutteres resource and collaboration effectivness.


2. Working Directory Linking:


Changing the working directory (Location of where the application starts the process of the build and runtime).

Steps:

  • Open Project Properties (Right-click on the Solution -> Project Properties in Visual Studio).
  • Navigate to Configuration Properties -> Debugging -> Working Directory.
  • Add the folder (DLLs) to specify that the project starts building from the (DLLs) folder instead of the root directory.

Running locally through (IDE) debugger:

  • Has no requirements as long as the DLLs are located there when they are asked by the application.

Running from Output Directory:

  • Requires the (DLL) directory to be built into the output directory for the .exe to locate it.

See the bottom of the page to setup Pre-linking Events.

Advantages:

  • Allows the user to define a costum (DLL) folder up in one directory of the (Root directory).
  • The project starts from the (DLL) folder.

Cons:

  • Requires that the user builds the folder into output directory aiming to run it from an .exe
  • The user is limited to one folder of (DLLs), and can not define Debug from release versions.


3. Defined locations (PATH):


Giving the (IDE) or application a pre-defined location to look for dlls.

The following should be used if the aim is to specify multiple location or versions of dlls for the application.

Steps:

  • Navigate to Configuration Properties -> Debugging -> Environment.
  • Specify a path as an example PATH=$(ProjectDir)\DLLs, where (ProjectDir) specifies the project root and \DLLs its folder.
  • This example the Working directory should be of $(ProjectDir) as listed in Root Directory Linking (Default):

Specify more than one path PATH=$(ProjectDir)\DLLs, PATH=$(ProjectDir)\DLLs2 by the use of ,.

See the bottom of the page to setup Pre-linking Events.

Advantages:

  • The user can define the locations of the dlls.
  • The user is not limited to changing the working directory.
  • The user can setup different dlls specific to debugging and release versions.
  • Project organization and file handling.

Cons:

  • Requires that the user builds the folder into output directory aiming to run it from an .exe (If located in a folder).
  • Path has to be the same in output directory as in project files.
  • May become difficult to remember the setup and how to change the specifics.


4. System directory linking:


The following is specific to the users machine, which may affect the project for collaboration and future development if the dlls are not made accessible in the system globally or not installed.

Please use it with caution and existing knowledge as it requires administrative privilages and can potentionally lead to breaking your computer.

The following should be used if and when for example you are testing your environments and projects on a local server, where additionally adding dlls may become unfavored.

Remember the following should not be done for basic development environment!

  • Most commonly the following is used by companies that are known, that automatically install new dlls into your system, such alike for example nvidia graphics drivers is being handled as the following must be accessible not only by the gpu, but also any potential video games.

Steps:

Access System Environment Variables:

  1. Right-click on the Start button and select System.
  2. Click on Advanced system settings on the left.
  3. In the System Properties window, click the Environment Variables button.
  4. Modify System’s PATH Variable:
  5. In the Environment Variables window, under the System variables section, find and select the Path variable.
  6. Click the Edit button.
  7. Add DLL Directory to PATH:
  8. In the Edit Environment Variable window, click New and paste the full path to the directory containing your DLL.
  9. Click OK to close each window.

When completed make sure to restart the system and or any applications you may have open.

If everything was done correctly, visual studio should now have access to globally linked dlls, this is because the search order of the (IDE) first takes through all of your APIs, appplication, known dlls and dependencies, if they aren ot found it looks for it through system32 path,

Please see on further reading at the bottom of the page

Advantages:

  • Makes your dlls accessible globally so that any project you make has access to them and avoid the setup each time.
  • You can rely on your own local dlls if not specified differently by the project.
  • One pre-defined location.

Cons:

  • Can cause potential mishaps within the system due to defined dlls
  • The dlls are only accessible locally.
  • If the DLLs folder goes missing, every other project reliant on it breaks!
  • Might cause issues with dll version as project(s) may require different patches.


Pre-Linking Events


  1. Building DLLs into output Directory:
    • Navigate to Configuration Properties -> Build Events -> Pre-link Events.
    • Use the Copy function to move files from the “DLLs” folder to the build root.
  2. Add the Following Command:
   copy "$(ProjectDir)DLLs*.dll" "$(TargetDir)"
   ping -n 6 127.0.0.1 > nul

2.1 Notes for Expanding

  • copy function to copy all DLL files (*.dll) from the “DLLs” folder in your project directory ($(ProjectDir)) to the target directory where the final build is stored ($(TargetDir))
  • Adjust the file path according to the folder names based on Configuration steps 1 or 2.

  • .dll Specifies that all with an extentsion of it should be added to the build.

  • Specify further copy in the next line, depending on the amount of DLL dependencies change the ping of -n 6

  • Alternativly the specification for specific dll can be called as such copy "$(ProjectDir)DLLs\YourDLL1.dll" "$(TargetDir)", which instead using all in the directory calls the specified .dll file.

  • ping -n 6 127.0.0.1 > nul
  • Used to add additionaly day to ensure, that the project has sufficient time to link and build “dynamic libraries “ DLLs
  • ping command, essentially specifying a delay with amount.
  • -n 6 by 6 seconds
  • 127.0.0.1 Loopback address, send loop to Address of 6 times with a delay of 6 seconds.
  • > nul Supresses output from the display (Directing the output to void)


And Example for Path and working directory DLL In Folder Example
The following guide is based on an (IDE) Visual Studio 2022
Visual studio Build Events

Read about Working directory Source Documentation by Microsoft “ Dynamic link library search order. “

Read more about different types of Linking:
Compile-Time Linking, Runtime Linking

Author: VerzatileDev

Published: 08/02/2024

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Last Modified: Friday, 23 February 2024 12:57:45

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