Powershell cheatsheet for C++/C#

This is just a small post to help my ageing memory remember where things are located.

  • Powershell C#
    Locate the dll, System.Management.Automation.dll, and add it to your project, (or add it via Nuget).

    • See this blog for a good introduction on creating a project, (works for vs2015).
  • Check what version is installed
    • According to the official site you need to check the registry
      HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell\1
      or
      HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell\3
      And check that the value Install is set to ‘1’.
  • Debuging
    • The external program is C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe
    • But the actual location is:
      • Powershell 1: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell\1\PowerShellEngine\{ApplicationBase}
      • Powershell 3:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell\3\PowerShellEngine\{ApplicationBase}
    • Launching from debuger:
      • For a script:
        PowerShell -Command “& {.\myscript.ps1}” or
        PowerShell -File “.\myscript.ps1”
      • For a CmdLet/Module:
        -noexit -command “&{ import-module .\AMPowerShellCmdLets.dll -Verbose}”
  • Some links

What I had forgotten about WM_CLOSE

When I was working on the next version of Piger I would sometime get an issue when using the this.bye command, (to close Piger).

What happens in the background is I call WM_CLOSE to close the active window, this message is sent to all the windows.

When it is processed by the message pump no other messages are been processed, this is a problem in case some windows are still dishing out messages, (like a fading dialog box in our example).

So remember, once you call WM_CLOSE, all bets are off and your message pump is as good as dead.

Best to have your own ‘Close()’ that does all the housekeeping in the background before you actually post WM_CLOSE to the main thread…

Otherwise your app my appear to hang.

Embed Python in your C++ application without Python installed on guest machine

For my Piger application, I wanted my C++ app to parse Python scripts but I quickly became aware of the fact that the user must have Python installed on their machine, not only that they needed the same version as mine, (version 3.5).

The normal call would be something like…

#include <Python.h>
...
// This will cause an error if the user does not have the same version of Python as the one we want.
// or if they do not have Python installed at all.
Py_Initialize();
...

But that throws an error when the user does not have Python installed.
And if they have an older version installed, it _might_ work, but the scripts might not work as expected.

The solution is to embed the Python you want to run in your app.

  1. Go to the Python website and download the Embeddable zip file for your app, (x64 or x86)
  2. Extract the python35.zip located inside that zip file
  3. Copy it somewhere where it can be referenced.
  4. Add the code below.
#include <Python.h>
...    
std::wstring exe_dir = L"\\exe\\path";
std::wstring python_path;
python_path += exe_dir + L"python35.zip";
Py_SetPath(python_path.c_str());

// Now we can call Initialize
Py_Initialize();
...

Now your app will work using version Python 3.5.1

Include Google test to your vs2015 project

To include Google test to your visual studio project you just need to follow the steps below

  1. Download Googletest from Github and copy all the file in it’s own folder.
    You only need the folder called “googletest” other files are for github and so on.
  2. Create a library
    1. Add a new empty project
      Right click the solution, Add > New Project …, “Win 32 project”
    2. Give it a name “googletest”
    3. Make sure that the directory is relative to your project, (the default is somewhere weird and wonderful in your %appdata% I think).
    4. Select the option “Static Library”, “empty project” and it should have no files in it.
    5. Uncheck the “Precompiled header” and press “Finish”
    6. Add gtest_main.cc and gtest-all.cc to that project, (they are located in the googletest\src\ folder of the files you just downloaded.
    7. Compile that project, and note where the googletest.lib file is created.
  3. In your test project,
    1. Right click > Properties > C++ > General
    2. In the part for “Additional include libraries” add the path to the google test folder and include folder.
      For example, “..\googletest\include;..\googletest\”.
    3. There might already be a folder called “%(AdditionalIncludeDirectories)”.
    4. Right click > Properties > Linker > General
    5. In the part for “”Additional Library directories” add the directory where the googletest.lib file was created, (the library, not the file).
    6. Finaly, add a reference, (Right Click the project > References and add googletest).

Be sure to set the references and include libraries for all your configurations, “Release”, “Debug”, x32, x64 and so on.

NB: Of course you can just build the lib and include it as a library, but that way when Googletest does an update, you just need to replace the code, and life is good again!