I'm creating simple web service client in CPP. I have generated source files from WSDL with help of svcutil ans wsutil utilites. At the end I got web service interface header and C file.
When I include C file into my console application that uses precompiled header I have message:
Error 3 error C1853: 'Debug\TestLib3.pch' precompiled header file is from a previous version of the compiler, or the precompiled header is C++ and you are using it from C (or vice versa)
How to solve this problem?
The C compiler cannot use a .pch file that was generated by the C++ compiler. Two basic options:
Rename the .c file to .cpp, likely to work fine on an auto-generated source file.
Right-click the .c file in the Solution Explorer window, Properties, C/C++, Precompiled headers, "Precompiled Header" option. Change it to "Not using". You may also need to modify C++ source files that #includes the .h file, it is liable to require extern "C" {} around the #include directive so the C++ compiler knows that the .h file contains C declarations. You'll know this is needed when you get linker errors that show the mangled name of the function.
Related
I have C++ file header (interface.hpp) in my Objective-C project.
When I use it I get a compiler error on the line: #include <map>
map file not found
and it's the same for #include <string>
string file not found
It seems to me that, despite the file extension hpp, Xcode is compiling it as C header, rather than C++ header.
Any suggestion?
The extension of the header is irrelevant. What is important is the extension of the file that includes that header. If you want to include a C++ header in Objective-C code, you need to change the extension of the Objective-C file to .mm. This indicates that the file is an Objective-C++ source file (a different language, in fact, so be careful that you know what you're doing). Headers that are included in a .mm file will be parsed as Objective-C++, and so then your C++ constructs should work.
You have to change the file extension to .mm in order to use it.
If changing the extension to .mm is not working try adding -l"c++" to Other Linker Flags in build settings.
I have a question about using C++ header files in Objective-C++ modules in Xcode. Specifically, why can I #include them in source files but not header files?
Here is a specific example.
I'm using Xcode 7.2.1 and have two projects. The first is a C++ framework I package into "myFramework.framework". It exposes "myFramework.h", which in turn pulls in "myLib.h". At the top of "myLib.h" is an "#include <string>".
The second project is an Objective-C iOS app which consumes the above framework. In this project, "myViewController.mm" (Objective-C++ source) has "#import "myFramework/myFramework.h" at the top and makes reference to things defined in that header file.
At this point all is well and good. It builds and runs with no issues.
When I move the "#import myFramework/myFramework.h" line to "myViewController.h", the compile fails because it cannot locate the "" header dependency.
It doesn't matter if I change the file type for "myViewController.h" to Objective-C++ header from plain old "C Header". Either way, Xcode's header search paths don't look for standard C++ headers.
So my main question is why does it behave this way? Why is a #include/#import treated differently just because it's in a header file?
My second question is if there's some way to make Xcode treat the #include/#import the same when it's in the header file instead of the source file?
Thanks much!
Are you sure that you get the error while compiling the myViewController.mm file?
Check if myViewController.h is imported into some other, non ObjC++ file (and that that one is the file that fails to compile).
I suspect the issue with including C++ headers inside other headers is that an Objective-C source file gets to see the C++ header file, which upsets it.
If you have mixed C++/Objective-C++/Objective-C then you are probably better off only exposing a pure Objective-C interface to other modules in the project and include any C++ header files in the Objective-C++ source files only.
Alternatively make everything Objective-C++ and then you don't need to worry about it at all.
Hopefully this answers your second question as well.
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.
So I have a .h file and when I include iostream xcode says that header file doesnt exist. But what is making me mad is that whenever I go though the new file process choosing c++ class the default .h file comes with one line of code, which includes iostream.h
so when I import that to my Objective-C code it fails to compile.
If you put #include <iostream> in a .h file, then you must be sure to only include that .h file in C++ files (.cpp or .cc) or Objective-C++ files (.mm). You're getting a compiler error because you're including your .h file in a C (.c) or Objective-C (.m) file.
I've made a struct which does cached file manipulation for my application. I built and tested to in a separate project before putting it into my current one.
Ever since I've moved it over, Xcode refuses to build it. Except when I don't include the file from any Objective-C based header file.
I get one error when I try to include iostream:
And more when I comment it out:
Its file extension is .mm, however I have tried it with .cpp and .hpp, but all of them refuse to build unless I don't #include it from the Objective-C header file.
I've also tried #import from iostream and the file itself in the Objective-C header file.
Any clues as to why this is happening?
As a matter of principle, you cannot include a C++ header file from an objective-C source file.
After all, #including (or #importing) a file only means that the preprocessor replaces the #include directive by the contents of the #included file, before passing the result on to the "actual" compiler. The file extension of the header file is a matter of convention, only, it has no actual meaning.
The error messages your are seeing are clearly the result of the file being compiled as [Objective-]C rather than [Objective-]C++.
Solution: All the source files that include your C++ header file have to be either C++ (.cpp or .cc or a few other extensions) or Objective-C++ (.mm). All source files that include a header file that includes your C++ header file, also have to be C++ or Objective-C++.
EDIT: I just saw that you are defining non-inline, non-template functions in your C++ file that you want to include. This is an unrelated problem, but it will lead to "multiple definition" errors sooner or later. Those function definitions belong in a .cpp, which shouldn't get #included anywhere, only the struct/class definition belongs in a header.
Take a look here and here. You need to tell the compiler to include libstdc++. When mixing Objective-C and C++ all you're files need to have the ".mm" extension, as stated in the second link.
I suspect the error is occurring when you compile a .m or .c file that includes the same header.