According to Microsoft ( https://learn.microsoft.com/en-us/cpp/overview/visual-cpp-language-conformance?view=msvc-160 ), it implemented P1502R1 Standard library header units for C++20:
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1502r1.html
in the latest Visual Studio 2019.
So one can write, e.g.:
import <vector>;
But if I do it in my Visual Studio 2019 16.10.3 (with /std:c++latest switch), the following compilation error arises:
error C7612: could not find header unit for 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30037\include\vector'
The complete command-line in Debug configuration:
/JMC /experimental:module /external:env:"EXTERNAL_INCLUDE" /permissive- /ifcOutput "x64\Debug\" /GS /W4 /Zc:wchar_t /ZI /Gm- /Od /sdl /Fd"x64\Debug\vc142.pdb" /Zc:inline /fp:precise /D "_DEBUG" /D "_CONSOLE" /D "_UNICODE" /D "UNICODE" /errorReport:prompt /WX- /Zc:forScope /RTC1 /Gd /MDd /std:c++latest /FC /Fa"x64\Debug\" /EHsc /nologo /Fo"x64\Debug\" /Fp"x64\Debug\Project1.pch" /diagnostics:column
Please help how to activate this new feature in MSVC?
Related
I have a solution with two one-source-file projects in it. Each file is:
#include <mosquitto.h>
The first compiles fine. The second says it cannot find a header. The source code in the second is identical to the first, so it is a mystery why it cannot compile.
Pre-compiled headers are not being used in either, so it is curious that the /Fp option is issued, I don't see how it can be playing a role.
/permissive- /ifcOutput "x64\Release\" /GS /GL /W3 /Gy /Zc:wchar_t /I"C:\Program Files\mosquitto2.0.14\devel" /Zi /Gm- /Od /sdl /Fd"x64\Release\vc143.pdb" /Zc:inline /fp:precise /D "NDEBUG" /D "_CONSOLE" /D "_UNICODE" /D "UNICODE" /errorReport:prompt /WX- /Zc:forScope /Gd /Oi /MD /FC /Fa"x64\Release\" /EHsc /nologo /Fo"x64\Release\" /Fp"x64\Release\Good.pch" /diagnostics:column
/permissive- /ifcOutput "x64\Release\" /GS /GL /W3 /Gy /Zc:wchar_t /I"C:\Program Files\mosquitto2.0.14\devel" /Zi /Gm- /O2 /sdl /Fd"x64\Release\vc143.pdb" /Zc:inline /fp:precise /D "NDEBUG" /D "_CONSOLE" /D "_UNICODE" /D "UNICODE" /errorReport:prompt /WX- /Zc:forScope /Gd /Oi /MD /FC /Fa"x64\Release\" /EHsc /nologo /Fo"x64\Release\" /Fp"x64\Release\Bad.pch" /diagnostics:column
Another user suggests posting the actual failed output.
Build started...
1>------ Build started: Project: Bad, Configuration: Debug x64 ------
1>Bad.cpp
1>T:\MyFirm\dev\MinorProjects\Bad\Bad.cpp(55,10): fatal error C1083: Cannot open include file: 'mosquitto.h': No such file or directory
1>Done building project "Bad.vcxproj" -- FAILED.
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
I turned on Tools->Options->Projects and Solutions->Build and Run->verbosity=Detailed, and compared the CL.exe commands issued.
To my surprise, the /I include option was NOT present on the failed build command, despite being in the Properties dialog "Command Line" page as pasted above.
The issue was that I was building in Debug, but for some reason the Properties dialog was editing Release options. So, while the "Command Line" page was showing the options that would be used were I building Release, they weren't used while building Debug.
Consider code:
#include <stdio.h>
int main() {
int a = 4;
#if 1
printf("Hello world\n");
#endif a++;
printf("a is %d\n", a);
}
Inadvertently, statement a++; is on the same line as a #endif and is not evaluated. As a result, the final output is:
Hello world
a is 4
On x86-64 clang 12, this is captured as a warning with using option -Wextra-tokens. See here.
I tried compiling this on Visual Studio 2019 MSVC, with command line options:
/JMC /permissive- /ifcOutput "Debug\" /GS /analyze- /W3 /Zc:wchar_t /I"../include/" /ZI /Gm- /Od /sdl /Fd"Debug\vc142.pdb" /Zc:inline /D "WIN32" /D "_DEBUG" /D "_CONSOLE" /D "_UNICODE" /D "UNICODE" /errorReport:prompt /WX- /Zc:forScope /RTC1 /Gd /Oy- /MDd /FC /Fa"Debug\" /EHsc /nologo /Fo"Debug\" /Fp"Debug\windows.pch" /diagnostics:column
There is no warning of any sort on compilation. Is there a setting that can be passed to the compiler in MSVC that detects extra tokens?
Edited to add:
As answered by user Nathan Pierson, it was indeed option /Za that worked. It does not seem to be on by default. I was also unable to use the Visual Studio Project Properties dialog to find out the option to set. Yet, one can feed in extra options manually thus:
There's compiler warning C4067. It looks like you need to set the flag /Za for it to apply to #endif directives.
In the Visual Studio properties page, this flag is controlled by the setting "Disable Language Extensions" in the Language subsection of the C/C++ section.
I'm trying to build my dll file as x64, here are the configurations I have done on VisualStudio:
I have set solution and project platform to x64:
According to this answer, I have changed naming convention from __cdecl to __fastcall:
According to this comment I have added the argument _WIN64 to Preprocessor Definitions:
But still, when I rebuild my project and open my dll file using notepad, I see PE L which means my dll file is 32 bit.
Here's the command line options of the C/C++ settings (for better reading, I put a couple of line breaks in there):
/JMC /permissive- /GS /W3 /Zc:wchar_t /ZI /Gm- /Od /sdl
/Fd"x64\Debug\vc142.pdb" /Zc:inline /fp:precise /D "_WIN64" /D "_DEBUG" /D
"_CONSOLE" /D "_WINDLL" /D "_UNICODE" /D "UNICODE" /errorReport:prompt /WX-
/Zc:forScope /RTC1 /Gr /MDd /FC /Fa"x64\Debug\" /EHsc /nologo /Fo"x64\Debug\"
/Fp"x64\Debug\DllCall-CppConsoleApp-1.pch" /diagnostics:column
Linker settings:
What should I do?
I have 2 very similar projects (concole Visual C++) but in one of them in the Release Mode I am getting the error:
managed targeted code requires a '/clr' option
I am comparing the Properties C/C++ command line:
The error Project:
/Zi /nologo /W3 /WX- /O2 /Oy- /GL /D "WIN32" /D "NDEBUG" /D "_UNICODE" /D "UNICODE" /Gm- /MT /GS- /fp:precise /Zc:wchar_t /Zc:forScope /Fp"Release\airl.pch" /Fa"Release\" /Fo"Release\" /Fd"Release\vc100.pdb" /FU"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.0\System.Core.dll" /analyze- /errorReport:queue
The No Error (good) Project
/Zi /nologo /W3 /WX- /O2 /Oy- /GL /D "WIN32" /D "NDEBUG" /D "_CONSOLE" /D "_UNICODE" /D "UNICODE" /Gm- /EHsc /MT /GS /fp:precise /Zc:wchar_t /Zc:forScope /Fp"Release\prj.pch" /Fa"Release\" /Fo"Release\" /Fd"Release\vc100.pdb" /Gd /analyze- /errorReport:queue
There are a few differences, but I do not know how to remove
/FU"C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.0\System.Core.dll"
What about Gd option in the good configuration?
I have a small test project that I want to build with TeamCity. In TeamCity I have created a build step with runner type 'Visual Studio' solution. The problem is it is not building. The error I get is:
error C1069: cannot read compiler command line
Here a part of the build log:
[16:55:05]ClCompile
[16:55:05]CL
[16:55:05]C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\CL.exe /c /ZI /nologo /W3 /WX- /sdl /Od /Oy- /D WIN32 /D _DEBUG /D _LIB /D _UNICODE /D UNICODE /Gm /EHsc /RTC1 /MDd /GS /fp:precise /Zc:wchar_t /Zc:forScope /Fo"Debug\\" /Fd"Debug\vc120.pdb" /Gd /TP /analyze- /errorReport:queue UnitTest.cpp
[16:55:05]UnitTest.cpp
[16:55:05]c:\data\teamcity buildagent\work\d8c46b39964cb4dc\testlibrary\unittest.cpp(27, 0): error C1069: cannot read compiler command line
Try removing the space in the TeamCity build agent path:
c:\data**teamcity buildagent**\work\d8c46b39964cb4dc\testlibrary\unittest.cpp
There is a bug with the VS2013 compiler as documented here:
http://social.msdn.microsoft.com/Forums/vstudio/en-US/82304c15-37e2-4761-8928-0c67e074bf47/error-c1069-cannot-read-compiler-command-line-on-visual-studio-2013-rc?forum=vcgeneral
(Note, this is referring to the RC and could now be fixed)