I just have a quick question. I've noticed that I don't have stdafx.h in my compiler(mingw32 on windows)
Am I supposed to have it? Or maybe is there a way to get around it?
Thanks for reading
EDIT: ok here is my current build log once I took out ALL of the includes of stdafx.h
http://pastebin.com/bczLr8xY
Read this wikipedia article. The paragraph I linked and the paragraph below it (mingw32 uses GCC).
http://en.wikipedia.org/wiki/Precompiled_header#stdafx.h
Since stdafx.h contains the most common headers I would remove every instance of #include stdafx.h and try to compile. If you get compile errors that a certain function is missing, add the appropriate header. Rinse and repeat.
No. Stdafx.h is created with MSVC++. It usually contains most common headers files. And Stdafx.h is included in every .cpp file in the beginning. It's precompiled header (if you've chosen so in the settings) created by MSVC++.
To all:
Using the pre compiled header file stdafx.h in the visual C++ always creates one or the other problem n case u have created a "Windows Console App" from Visual C++.
The Solution to it is that, just create "Empty Project", rather than the pre-compiled windows console application. After creating the Empty project, create the source File. Write the business logic and add all the required resource and header files. Keep the external dependency files in the same directory in which your source code is: e.g., C:\Users\John\Documents\Visual Studio 2010\Projects\xyz.cpp\xyz.cpp.
Finally add the source file to the global scope, that is add it to the "Empty Project" created already. It can be done by Clicking "File" on Visual Studio prompt and select the option of adding the source file to the project.
Thanks and Regards:
Rouf Khan
Related
So I have been trying to learn cpp and I was writing a program, and when I try to build the solution, it gives an error saying
unexpected end of file while looking for precompiled header. Did you forget to add #include "pch.h" to your source?
Then I included it and I got the same error, and also another saying
cannot open source file pch.h
One option, if you are new to c++, is to just turn off pre-compiled headers in the project settings.
It needs to be the first include, you can't place it under other includes.
Your .cpp file is probably not in the same directory as pch.h
Try adding the directory that your pch.h is in to the additional includes, even if it is at the root of your project.
quick solution to a frustrating issue when trying to add .pch to an exisiting project:
if you have a /include /src dir structure, it might not work,
unless you place the "pch.h" and "pch.cpp" in the same dir /src.
Also: mark the "MyPreComp.cpp" as /Yc - create,
and in the .cpp files you want to use the .pch set them to Yu - use.
#include "pch.h" as the first #include in the .cpp
NB. You need to set "not using precompiled headers" to all .cpp files not using them,
yes, it IS a hassle.
( Visual Studio 2019 )
It needs to be included to each cpp file (by default)
It needs to be included in the very first line of your code (excluding the comments, it's ok to have the fancy comments on top)
It needs to be in a reachable directory. This error often happen when you have a folder structure in your project. So this can happen with a source files in some nested folder, when your precompile-header-file is up there in main. In this case, either add necessary number of "../" before the file name, or add the main folder to the "additional include directories" as it is already suggested above.
It needs to actually be the same precompile header file, that is set as the one in project setting. Check the file with "Precompiled Header" option set to "Create (/Yc)", ensure that it refers to he same header file, that you include ("pch.h" or "stdafx.h" by default) This error often happens when you include some old source to newer proj, or vice-versa, due to different default names in different studio versions: "stdafx.h" vs "pch.h".
If all above is set up, and you still have it, check if you actually set it up for the right build configuration. Always apply project setting change for all configurations. Costed me some nerves when I did it for only one config, and was trying to compile another:
When I build my c++ solution in Visual Studio it complains that the xxxxx.pch file is missing. Is there a setting I am missing to get the pre-compiled headers back?
here is the exact error for completeness:
Error 1 fatal error C1083: Cannot open precompiled header file: 'Debug\xxxxx.pch': No such file or directory
NOTE: Later versions of the IDE may use "pch" rather than "stdafx" in the default names for related files. It may be necessary to substitute pch for stdafx in the instructions below. I apologize. It's not my fault.
Right-click on your project in the Solution Explorer.
Click Properties at the bottom of the drop-down menu.
At the top left of the Properties Pages,
select All Configurations from the drop-down menu.
Open the C/C++ tree and select Precompiled Headers
Precompiled Header: Select Use (/Yu)
Fill in the Precompiled Header File field. Standard is stdafx.h
Click Okay
If you do not have stdafx.h in your Header Files put it there. Edit
it to #include all the headers you want precompiled.
Put a file named stdafx.cpp into your project. Put #include "stdafx.h"
at the top of it, and nothing else.
Right-click on stdafx.cpp in Solution Explorer. Select Properties
and All configurations again as in step 4 ...
... but this time select Precompiled Header Create (/Yc). This will only
bind to the one file stdafx.cpp.
Put #include "stdafx.h" at the very top of all your source files.
Lucky 13. Cross your fingers and hit Build.
Precompiled Header (pch) use is a two-step process.
In step one, you compile a stub file (In VS200x it's usually called stdafx.cpp. Newer versions use pch.cpp.). This stub file indirectly includes only the headers you want precompiled. Typically, one small header (usually stdafx.h or pch.hpp) lists standard headers such as <iostream> and <string>, and this is then included in the stub file. Compiling this creates the .pch file.
In step 2, your actual source code includes the same small header from step 1 as the first header. The compiler, when it encounters this special header, reads the corresponding .pch file instead. That means it doesn't have to (re)compile those standard headers every time.
In your case, it seems step 1 fails. Is the stub file still present? In your case, that would probably be xxxxx.cpp. It must be a file that's compiled with /Yc:xxxxx.pch, since that's the compiler flag to indicate it's step 1 of the PCH process. If xxxxx.cpp is present, and is such a stub file, then it's probably missing its /Yc: compiler option.
Fix:
Make sure you have xxxxx.cpp in your project
Compile xxxxx.cpp with /Yc flag (Create Precompiled Header)
(right click on xxxxx.cpp -> properties -> Precompiled Headers -> create)
Compile all other files with /Yu flag (Use Precompiled Header)
(right click on project -> properties -> Precompiled Headers -> use)
Right click to the project and select the property menu item
goto C/C++ -> Precompiled Headers
Select Not Using Precompiled Headers
Yes it can be eliminated with the /Yc options like others have pointed out but most likely you wouldn't need to touch it to fix it. Why are you getting this error in the first place without changing any settings? You might have 'cleaned' the project and than try to compile a single cpp file. You would get this error in that case because the precompiler header is now missing. Just build the whole project (even if unsuccessful) and than build any single cpp file and you won't get this error.
In case this is happening to you on a server build (AppCenter) and yo uaer using CocoaPods ensure that your Podfile is checked in.
AppCenter only runs the "pod install" command if it finds a Pofile and it DOES NOT find the PODS folder on the files.
I had the folder checked-in, but because git automatically ignores .pch files (check you .gitignore to veryfy this), my .pch weren'nt being checked in.
I sorted my issue by forcing the .pch files to check it, but Deleting the PODS folder should work too, since Appcenter will run the pod install command in that case.
Hoppefully this helps somebody.
VS screwed (mine is 2019 ;( ).
Go ahead and choose "not using precompiled headers" as other guys are pointing out then open the project file (vcxproj) with any text editor, and delete the outlined two entries in two places. Enjoy cleaning up the mess!
As a matter of fact, the 'pch.h' entry in the vcxproj file you see it below, you will ever find it in VS properties' interfaces.
Try Build > Clean Solution, then Build > Build Solution. This works for me.
I know this topic is very old, but I was dealing with this in VS2015 recently and what helped was to deleted the build folders and re-build it. This may have happen due to trying to close the program or a program halting/freezing VS while building.
I was searching for the iOS PCH file having the same problem, if you got here like me too, the solution that I've found is by clearing derived data; Close Simulator(s), go to xCode prefs -> locations -> go to the derived data file path, close xCode, delete the files in the derived data folder, re launch and cheers :)
I managed to create this problem for myself because I wanted to use a pch.h and pch.cpp file from different directories. So, I deleted the two files from my project and then added them as existing files from somewhere else. Big mistake as precompiled header files can no longer be found.
There is no way that I can find to fix the problem from the Visual Studio 2019 UI. You must edit the project file and make sure the following look like this:
<ClCompile Include="pch.cpp">
<PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">Create</PrecompiledHeader>
<PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">Create</PrecompiledHeader>
<PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">Create</PrecompiledHeader>
<PrecompiledHeader Condition="'$(Configuration)|$(Platform)'=='Release|x64'">Create</PrecompiledHeader>
</ClCompile>
I had same issue, and I managed to solve it like this:
ERROR :
fatal error C1083: Cannot open precompiled header file : "Debug\myProj.pch". No such file or directory
first one is when I had an error,
and changed it like a second picture
make (/Yx)
myProj.h
In my case, it was necessary to select Create (/Yu), instead of the standard Use (/Yu)
to
If everything is right, but this mistake is present, it need check next section in ****.vcxproj file:
<ClCompile Include="stdafx.cpp">
<PrecompiledHeader Condition=
In my case it there was an incorrect name of a configuration: only first word.
I understand what precompiled headers are doing with "#include "StdAfx.h" and yes, I know I can turn them off. But that's not my question.
If you're using precompiled headers, Visual C++ requires every cpp file to #include "StdAfx.h", even the files that aren't using any of the headers in StdAfx.h. If you forget to include StdAfx.h on one file, it's an error. But why? The obvious approach would be just "If you include StdAfx.h then that file will use it, but if you forget to include it, then those header files will simply not be included." I don't understand why VC++ would require you to include StdAfx.h when it's not needed. Seems like it would have been easier for them to treat it like a normal header file.
Is there any good reason why this is required?
Just a addition to the Marks answer. In fact, you do not have to manually include stdafx.h in the all project source files. You may use project option Forced Include Files:
That way stdafx.h will be automatically included in all your sources.
Your project default is "use precompiled headers". You can set individual files to "not use precompiled headers" if you desire.
In fact, stdafx.cpp itself has a different option from the project defaults:
What this configuration is saying is "start compiling this file (stdafx.cpp), stop when you finish compiling the statement that includes stdafx.h" and save the precompiled information as as .pch file." Visual studio is also smart enough to compile this file first so it is available for use.
The project defaults are:
What this configuration is saying is "For each compiled file, start with the precompiled data in the specified .pch and start compiling new information after the point stdafx.h is included." That's important and why stdafx.h should be included as the first line of the file. It will still work if you put it later in the file, but anything before the #include is ignored because that data won't be in the .pch. Absence of the #include means VS will scan the whole file looking for the pre-compiled starting location and not find it...generating an error.
If you have a file that you don't want to use pre-compiled information, you can select the file and override it. Example:
Visual Studio won't use the precompiled information and won't look for a header to include.
When you select the file, right-click properties, go to the "C/C++ \ Precompiled Headers" section and set "Precompiled Header" to "Not using Precompiled Headers", be sure that the Configuration (top left) is applicable to the current selected build.
It doesn't always automatically select the "active" configuration; so you could be setting the option for a non-active configuration so you will continue to experience the error ;)
I am having a problem of getting compile errors (red underlines) like:
Error: cannot open source file "stdafx.h"
Here an edited screenshot of the environment:
On the LEFT is my Visual Studio Solution Directory list with the "Show All Files" off.
I am working on a school project, and each Folder are the source files of different parts of the project with different people who are in-charge of them.
For example, Student A and B are incharge of AST and PARSER folders (we will call them sub-projects).
We have an API for each sub-project so other sub-projects know what to call.
At the TOP-CENTER, we have my Source File for a class QueryProcessor. (just the first few lines)
Below it, is the Output for the Build Success.
The red lines are all over all the classes, mainly cause the #include "stdafx.h" cannot be opened by the environment.
On the RIGHT, that is the stdafx.h where we include all the different sub-projects so we save the trouble of each project having a different stdafx.h
However, I am able to build the project. I am pretty sure I am doing this directory/linking wrongly.
This should work
Right click on the solution file
Click Open in Windows Explorer
Find file stdfx.h in explorer and copy the path of the folder
In visual studio solution explorer, Right click on the project file
Click properties-> C/C++ -> General
In the Additional Include Directories paste the path
Combining folders and virtual folders in VC is from my point of view messy because the virtual folders indicate that all files are in one directory and the folders created on the harddrive obviously indicate that all files are in different directories. You can combine it if you know what's going on but in your case I would not recommend it.
I assume you missunderstand the purpose of stdafx.h The purpose of this header file is NOT to put all header filles into it and then just include it to all other files. Here is a SO question about this Purpose of stdafx.h
After cleaning up your stdafx.h file include as many header files into your .cpp files and only put these includes in your header files if they are required in the header file
Turn on show all files, now you will work with actual folders and you can be sure that if you adress a folder like "PKB" that this folder really exists since you can see it in the left solution explorer.
If you use using namespace std; for example make sure you also include the required header files. You might think "hey I already included e.g. iostream in another header file which I now include in this header file so I don't need it" That will really destroy you when you work with bigger projects.
Oh and regarding the stdafx.h include problem as soon as you switch to show all files I assume you will realise that stdafx is in a different file than the file where you use the include. Maybe something like #include "..\stdafx.h" is required (depending on your structure).
I think it's obivious but if you include a header file the include is allway relative to the file which is including the other header file.
stdafx.h is commonly used for creating a precompiled-header, which essentially is a compile-time optimisation such that the compiler will not continually compile these headers for every compilation unit.
If any of these headers changes, you will need to do a full system rebuild.
In reality it is preferable only to use it to include standard headers plus third-party headers (like boost libraries and similar) that you are not ever going to change.
You may decide that some of your own libraries are "set in stone" and can also be included.
Every project, i.e. every part of the project that is built into a separate unit (DLL or .exe) should have its own precompiled header and its own version of stdafx.h
Projects should only ever include their own .stdafx and not those of other projects, therefore this header file can also be used to define your dllexport macro.
When arranging your project headers you should be aware of:
1. Which headers are included externally
2. Which headers are only included internally, and are not even included indirectly externally.
The latter sort should include your stdafx.h file and should ideally not be in the same directory as those headers included from outside your project.
Is there a way to set Visual Studio solution parameters so it just create precompiled headers without building whole solution.
Specifically, it is a huge c++ solution with many projects in itself.
Thank you.
Only select the pch creator source file (usually stdafx.cpp), and compile that (Ctrl-F7, or right-click it and select 'Compile')
More info since it doesn't seem to be working for you:
In every project that uses a precompiled header, there is one source file that is used to create the pch file, and the rest only use the pch file. This source file usually only consists of one line:
#include "StdAfx.h"
"Stdafx.h" is the default precompiled header file name in Visual C++, it could be something else for you. If you compile "StdAfx.cpp" by itself, that generates a file with the name "Your_Project_Name.pch" (again, that's only the default). You should see it in the intermediate directory, the same one where all the obj files are. This is the precompiled header. If you did like I said, and selected 'Compile' and not 'Build', then no other files will be compiled, and no linking will take place.
If that still does not solve your problem, then I have no idea what you are asking.
Here's an article describing the benefits and how to set it up.
If you have larger projects, it is definitely worth the few clicks and the extra disk space.
The article says you need to add stdafx.h to all sources and headers; it's not correct. It's sufficient to add to sources - make sure it's the first line though as everything before it will be ignored.
The article does not mention it, but you'll be getting errors from sources that do not include the stdafx.h. You have a choice to resolve this error: you either add it, or exclude the source(s) from the precompilation process.
To exclude source files:
select source file(s) in the solution explorer; yes you can select more at once,
right click on the highlighted source file,
click properties from the pop-up menu,
select 'All configurations' from the combo-box on top,
under C-C++ configuration click 'Precompiled headers',
on the right-hand side select 'Not using precompiled headers',
click apply,
click ok.
Enjoy your new builds in a few seconds from here on (the first build will take longer).
If you right-click any Cpp files except stdafx.cpp from your project and set Excluded from build to Yes, it will only generate the precompiled header.
You can achieve the same result through the command line or if you create new project containing only your stdafx.cpp