I know there are a few topics about it but I haven't found the answer to my question.
So my question is in Visual Studio 2017, everytime I create a project it's created with the class pch.h and also creates pch.cpp.
I would like to change the name of pch.h to a more pertinent name but it seems to always be looking for pch.h even though I have modified all the #include references.
Thanks in advance!
Adjust the name of the precompiled header file in the Project Properties under Configuration Properties -> C/C++ -> Precompiled Headers.
Note that pch.cpp has property to generate precompiled header.
Basically you may set the properties if and what precompiled header you use differently for each file in your project.
Related
While creating a dll project in VS17, I see multiple files were created on initialization.
But whichever project on C++ I work on, I don't see any such files in their environment. How can I get rid of these files in my environment. Is there any workaround to remove them entirely or reduce these 4 files to one file to reduce mess?
Also before VS17 we used to have stdafx.h, it is mandatory to include this header but in few projects I couldn't find this file, is there any way to remove these initial files entirely?
When you create a new project in Visual Studio, a precompiled header file named pch.h is added to the project. (In Visual Studio 2017 and earlier, the file was called stdafx.h.)
For more details about pch.h and stdafx.h, I suggest you could refer to the Doc:
Precompiled Header Files
If you couldn't want to use precompiled header file, I suggest you could choose to not use precompiled headers (Configuration Properties > C/C++ > Precompiled Headers).
When you create a dll project, you also directly choose uncheck Precompiled header or check Empty project.
stdafx.h/cpp resp. pch.h/cpp are the default generated files for supporting precompiled headers. If you don't want them you can delete them. In order to compile you then have to go to your project settings Configuration Properties -> C/C++ precompiled headers and change the Precompiled Header setting to Not using Precompiled Headers.
Before you delete thos files, you should check the cpp/h file and put the include files into your files.
Now, I realized that I need a precompiled header for my project. However, at the beginning, I created my project as an empty project which doesn't have a stdfx.h header file. So, this is what I did:
- I created a header file name stdfx.h
- In that file, I included some libraries.
- I went to the project Property Pages -> C/C++ -> Precompiled header -> set the PRECOMILED HEADER option to Use (/Yu).
- Finally, I included stdfx.h in every cpp file.
It works. However, I am wondering if the stdfx.h file that I created myself works like the one that is automatically created by Visual Studio? I mean is it really a precompiled header which will save time when compiling or just a normal header file?
It's normally named stdafx.h, but it really doesn't matter. You can name your precompiled header whatever you want.
You are missing one final step.
You also need to create a stdafx.cpp. This is an empty file that only has a #include "stdafx.h" line.
For this particular file, right click on it in the Solution Explorer and select Properties. This will bring up a Properties page with settings specific to this source file (in inherits your project settings by default). For this particular file, select /Yc as the compiler option instead of /Yu for the Precompiled setting. If you don't do this, you may not observe the build speed improvements of precompiled headers.
When Visual Studio builds, it will build your stdafx.cpp file first. And along with that, it will build the .pch file that the other source files will pick up.
And while I'm here. The things to include in the precompiled header file are all the system and C/C++ runtime header files. (e.g. <windows.h>, <stdio.h>, <string>, <map>, etc...). You'll get the most gains by including all these files - since they never change from build to build.
You definitely can make stdfx.h by yourself or other precompiled header file (name is not really important). But you should follow some rules described in MSDN.
You can read more about precompiled headers in the Documentation
In Visual Studio 2015, I have a C++/CLI project with the following error:
"fatal error C1010: unexpected end of file while looking for precompiled header. Did you forget to add '#include "stdafx.h"' to your source?"
I turned off precompiled headers in the project options but it keeps giving me the same error. I even removed the name of the precompiled header file but it still says "stdafx.h".
Edit:
Yes, every source file indivuduially doesn't have it enabled.
Ok. Hans Passant found out what was happening:
The build configuration that I used to build it still had precompiled headers enabled.
You may have disabled it for the project, but each individual source file can have it's own specific compiler settings. It's also possible you disabled pre-compiled headers for a specific source file, erroneously mistaking that action for a project wide setting.
For each individual C/C++ file in Solution Explorer, right click on it and select "Properties". Under C/C++ -> Precompiled Headers, make sure the Precompiled Header setting is "Not using Precompiled Headers".
The right click on your Project name in Solution Explorer and select "Properties as well" Double-check that the project settings are the same.
And if there's a stdafx.cpp file, it likely has the "Create Precompiled Header" setting. You can typically remove this file if it doesn't have any relevant code in it.
Repeat all the same steps for each Solutions configuration (e.g. both Debug and Release).
I met the same problem (turned off precompiled in project properties but the error remains).
Solution:
open .proj file with any text editor and search for
<PrecompiledHeader>Use</PrecompiledHeader>
you will see that there are still some properties set to use it. Just replace word "Use" with "NotUsing" and problem fixed.
Microsoft Visual Studio 2015:
Right click on solution -> Configuration Properties -> C/C++ -> Precompiled Headers -> Precompiled Header => Not Using Precompiled Headers
In my case, I found the pch.h still set in: c++ -> advanced -> forced include files.
Anyhow, Andrew's solution is still the best. Just open the proj. file in a text editor and ctrl-f search for the filename causing the issue. Much easier than skimming through all the properties in vs.
I read the documentation in MSDN, but in the end I didn't get a clear idea what is the practical difference between them, exactly. Both seem to require stdafx.h to be added at the top of every *.cpp file.
I'm using VS2008.
Can anyone help clear things up?
Short summary of how to use PCH files in Visual Studio:
All cpp files in the project have to include stdafx.h (you can change this to something else if you wish)
Select project in Solution Explorer and in Properties -> C++ -> Precompiled Headers set 'Create/Use precompiled headers' to 'Use'. Hit Apply
While the Property Pages are still shown select stdafx.cpp in solution explorer and set the value to 'Create'
Well, I think that you must first understand the purpose of precompiled headers. In large projects, it can take ages to process all the headers required by a single client extension for example, so some people prefer to distribute the .pch files along with their libraries. In order to generate the .pch files, you use the /Yc compiler flag and the person who wants to consume your library will set the /Yu flag. See here and here for details.
I am trying to use MFC with ProC.
Functions.pc is where I do the ProC syntax to connect to the database. So I include the 'Functions.h' in the dialog model where I want to call the functions in 'Funtions.h'. And now I got this error.
Add directive to 'stdafx.h' or rebuild precompiled header
I understand that I need to include 'stdafx.h' to 'Functions.h' for it to work. And I did that. It can compile,but then when I try to run the program,it won't recognize the syntax of ProC created by the 'Functions.cpp' created. I don't really understand how to rebuild the precompiled header since I don't understand the codes in 'stdafx.h'.
The common way to use precompiled headers on windows is
Include system , third party headers or infrequently changing headers in stdadx.h
stdafx.cpp usually only includes stdafx.h
All your project cpp files include stdafx.h as the first header
Your project header files should not include stdafx.h
To trigger a precompiled header rebuild,
Modify stdafx.h and do an incremental build
Or Do a rebuild project
Found the solution myself. I need to set the properties of that .cpp file to not using any pre-compiled header.
Within VS 2012 you can set the properties of the Project, the Solution, or Source File(s) to not use Precompiled Headers. See attached graphic for how to do it...
VS Turn off Precompiled Headers
In VS2017, this error persisted until I switched Project Properties > Configuration Properties > C/C++ > Precompiled Headers > Precompiled Header setting from "Use (/Yu)" to "Create (/Yc)".
For the project setting, use:
"Create" for pre-compiled headers to be produced by the project
"Use" for pre-compiled headers produced by another project
For per-file settings, use:
"Create" for the stdafx.cpp file only
"Use" for all other .c and .cpp files