In my Visual C++ code I want to have /WX - "treat warnings as errors". This makes me deal with each warning, including C4996 - "X was declared deprecated" which I don't want to address - I don't want to change code at the moment and I don't want to disable C4996 so that it remains in the output. So ideally I'd like to have something like:
#pragma warning( ExcludeFromWX:4996)
so that all warnings except this one are treated as errors when /WX is used and this warning is just displayed and compilation continues.
Is it possible to get such behavior?
You might be able to reset the specified warning by using following pragma. I did not test it though and you did not mention trying this:
UPDATE
Changing the warning level should succeed
#pragma warning( 4 : 4996 )
This does not work:
#pragma warning( default : 4996 )
Related
I have just installed a fresh Visual Studio 16.10.3 and added Google Test to my command console app. Right of the bat, I get the following warnings:
Severity
Code
Description
Project
File
Line
Suppression State
Warning
C26812
The enum type 'testing::TestPartResult::Type' is unscoped. Prefer 'enum class' over 'enum' (Enum.3).
Tests
D:\C++\ConsoleTest\packages\Microsoft.googletest.v140.windesktop.msvcstl.static.rt-dyn.1.8.1.4\build\native\include\gtest\gtest-test-part.h
62
Warning
C26495
Variable 'testing::internal::Mutex::critical_section_' is uninitialized. Always initialize a member variable (type.6).
Tests
D:\C++\ConsoleTest\packages\Microsoft.googletest.v140.windesktop.msvcstl.static.rt-dyn.1.8.1.4\build\native\include\gtest\internal\gtest-port.h
1804
Warning
C26495
Variable 'testing::internal::Mutex::critical_section_init_phase_' is uninitialized. Always initialize a member variable (type.6).
Tests
D:\C++\ConsoleTest\packages\Microsoft.googletest.v140.windesktop.msvcstl.static.rt-dyn.1.8.1.4\build\native\include\gtest\internal\gtest-port.h
1804
Warning
C26495
Variable 'testing::internal::Mutex::owner_thread_id_' is uninitialized. Always initialize a member variable (type.6).
Tests
D:\C++\ConsoleTest\packages\Microsoft.googletest.v140.windesktop.msvcstl.static.rt-dyn.1.8.1.4\build\native\include\gtest\internal\gtest-port.h
1804
Warning
C26495
Variable 'testing::internal::Mutex::type_' is uninitialized. Always initialize a member variable (type.6).
Tests
D:\C++\ConsoleTest\packages\Microsoft.googletest.v140.windesktop.msvcstl.static.rt-dyn.1.8.1.4\build\native\include\gtest\internal\gtest-port.h
1804
Warning
C26812
The enum type 'testing::internal::Mutex::StaticConstructorSelector' is unscoped. Prefer 'enum class' over 'enum' (Enum.3).
Tests
D:\C++\ConsoleTest\packages\Microsoft.googletest.v140.windesktop.msvcstl.static.rt-dyn.1.8.1.4\build\native\include\gtest\internal\gtest-port.h
1804
I tried suppressing the warnings by surrounding #include "pch.h" as described here:
#pragma warning(push, 0)
#include "pch.h"
#pragma warning(pop)
However, that didn't work - instead, I only got an additional warning that
#pragma warning(pop): no matching '#pragma warning(push)' (C4193)
I also read the Broken Warnings Theory. Unfortunately, I have to admit that I do not understand it. I think this is the relevant section:
To suppress the warning in external headers, we need to both specify which headers are external and what the warning level in those headers should be:
cl.exe /experimental:external /external:I some_lib_dir /external:W0 /W4 my_prog.cpp
This would effectively get rid of any warning inside some_hdr.hpp while preserving warnings inside my_prog.cpp.
But where would I add these switches and what would be the correct path variable for googletest?
Thank you in advance for your help!
Instead of
suppressing the warnings by surrounding #include "pch.h"
you should use the warning pragma to surround both header files(gtest-port.h and gtest-test-part.h), which can be found in External Dependencies in Solution Explorer of the Visual Studio project. The detailed methods are as below.
Add the following code to the very beginning and end of gtest-port.h
#pragma warning( push )
#pragma warning( disable : 26495 )
#pragma warning( disable : 26812 )
// Original Code
#pragma warning( pop )
Similarly, add the following code to the very beginning and end of gtest-test-part.h
#pragma warning( push )
#pragma warning( disable : 26812 )
// Original Code
#pragma warning( pop )
In Visual Studio, warning C4996 (using a deprecated function) is treated as an error, and code that uses deprecated functions doesn't compile at all.
There are various ways to disable C4996 entirely, either suppressing it for a single line, for a translation unit, or for an entire project. But what if I want it to still raise a warning, but allow compilation while not treating it as an error?
#include <iostream>
[[deprecated]]
void deprecated_function()
{
std::cout << "I function, but have been deprecated.\n";
}
int main() {
deprecated_function();
}
This doesn't compile at all.
#include <iostream>
[[deprecated]]
void deprecated_function()
{
std::cout << "I function, but have been deprecated.\n";
}
int main() {
#pragma warning(suppress: 4996)
deprecated_function();
}
This compiles, but doesn't issue a warning at all.
Is it possible to tell Visual Studio to emit a warning, but still allow compilation, for a deprecated function? I'm thinking of refactoring purposes, where I'd like to mark a function as deprecated, identify all the places it's used, but the code still compiles at each intermediate stage where some but not all uses of the deprecated function have been replaced.
I'm compiling using Visual Studio 2019 Community 16.8.4, warning level set to /W3, "Treat Warnings as Errors" set to "No". This particular warning seems to be treated as an error if it gets emitted at all.
Found a working solution. It turns out the relevant flag is actually "SDL checks", not "Treat Warnings as Errors". Flipping it from /sdl to /sdl- causes compilation to emit a warning while still compiling.
EDIT: If I want to keep all the SDL checks on except treating Warning C4996 as an error, I can use the flag /sdl in combination with the flag /w34996, which specifies that 4996 is treated as a level 3 warning instead of an error.
The reason that I ask this question is this link below:
Why can this function return a C++ int reference?
It seems that the compiler is bad at reporting mistakes such as: return a value from a function.
So I want to activate them in Visual Studio 2019, but it did not work after I set it (restart IDE) like below:
I suggest you could try to use the following method to enable warnings that are off by default:
1,#pragma warning(default : warning_number )
The specified warning (warning_number) is enabled at its default level. Documentation for the warning contains the default level of the warning.
2,#pragma warning( warning_level : warning_number )
The specified warning (warning_number) is enabled at the specified level (warning_level).
3,/Wall
/Wall enables all warnings that are off by default. If you use this option, you can turn off individual warnings by using the /wd option.
4,/wLnnnn
This option enables warning nnnn at level L.
For more details anbout warning level, I suggest you could refer to the link:https://learn.microsoft.com/en-us/cpp/build/reference/compiler-option-warning-level?view=vs-2019
I am trying to eliminate the warnings in my project so I can turn on the flag that treats warnings as errors. The project uses the boost library, specifically the Concept_check.hpp and cuthill_mckee_ordering.hpp files. The warnings 4510 and 4610 are shown in the concept_check.hpp file and I have tried to disable them using #pragma warning push and pop. The warnings are caused by the boost library trying to instantiate a class using the template found in concept_check.cpp when there is no constructor written for it.
My Question is this: Is there a more sure fire way that I can disable these warnings without modifying the boost code? I am using Visual studio 2010.
Perhaps you are looking in the wrong direction. As Alan Stokes pointed out, the warning is there for a reason. I have three hints that are perhaps not the answers you expect, but may bring an acceptable solution:
Instead of silencing the warning, just fix the error. I don't know your code, but there are other people that had a similar problem which was possible to fix by just declaring a variable.
Another question is: why do you want to turn all your warnings into errors? Is it really neccessary? I agree that normal code should always compile without warnings. But these warnings are not originating from your own code. Consider a static code-checker that warns you about issues where your compiler is blind about.
If you have to use -WX, move the offending code into a static object/library/module so you will be bothered about the warning only when you need to recompile this module. You could use specific compile options for this module, to get the warnings completely out of your way.
There is another possibility, but I'm not able to check whether it really works. According the Microsoft Documentation it is possible to set the warning level of specific warnings. (there are similar options for GCC). First, switch all warnings to error:
/WX
Then, set the warning level of the two offending warnings to zero:
/W04510 /W04610
A complete commandline would look like this:
cl source.cpp /WX /W04510 /W04610
The best solution would be to combine this with hint 3 above. This way, the specific compiler options are only used for the files that cause the warnings.
Maybe these solutions work.
You can disable specific warning from a .h file (#pragma warning( disable: ... ).
I can inhibit many warnings in Visual Studio 2005 SP1 in the C/C++ Advanced property page, which causes the IDE to use the /wd switch on the command line which invokes the compiler. However, when I try to inhibit warning 4200 (nonstandard extension used : zero-sized array in struct/union), it still appears when I compile. (Of course it's justified; I'm just not in a position to fix the code, nor would it be worth bothering, because it's generated, and the warning is entirely benign under the circumstances.) Does anybody happen to know if this is a bug in the compiler? Or might there be something I can do about it?
To completely disable the warning in the file you can add the following to the top of the file
#pragma warning(disable:2400)
If you want some more flexibility other than a blanket disable for the file, the following page lists several other more fine grained options.
http://msdn.microsoft.com/en-us/library/2c8f766e(VS.80).aspx
It's unclear based on your information as to whether or not it's a bug in the compiler or a configuration issue. I would lean towards a configuration issue, specifically conflicting compiler options that is making it difficult to suppress the warning.
EDIT
OP mentioned they can't control the generated code so they can't directly include the pragma. If that's the case then try this trick. Say the file name is Generated.cpp. No longer include Generated.cpp as one of the files to compile. Instead create a new file called Example.cpp with the following contents
#pragma warning(disable:2400)
#include "Generated.cpp"
Now you'll get the text of Generated.cpp with the disabled warning by only compiling Example.cpp.
You mean like with pragma?
#pragma warning( disable : 2400 )