Solution-wide #define

Question

Is there a way to globally declare a #define?

Like I want to have a file that has for instance,

#define MONO

and I want all source-code files to know that this pre-processor directive is defined. How would I achieve that?

Answer 1

Update: You cannot do a "solution-wide" define afaik, however the answer below is workable on a per-project basis.

You set them in your Compilation Properties or Build options:

http://msdn.microsoft.com/en-US/library/76zdzba1(v=VS.80).aspx (VS2008) http://msdn.microsoft.com/en-US/library/76zdzba1(v=VS.100).aspx (VS2010)

see the "To set a custom constant" heading.

Update

Microsoft Documentation on Build Options

You get to the build options by right-clicking the project and selecting properties from the menu.

Answer 2

I know solution for C# projects (I don't tested it for any other projects)

For example you have:

Project1\
Project2\
Solution1\Solution1.sln
Solution2\Solution2.sln

Create SolutionDefines.targets file in solution directory

Project1\
Project2\
Solution1\Solution1.sln
Solution1\SolutionDefines.targets
Solution2\Solution2.sln
Solution2\SolutionDefines.targets
Solution3\Solution2.sln
Solution3\|no target file|

in each project file add:

<Import Project="$(SolutionDir)SolutionDefines.targets" Condition="exists('$(SolutionDir)SolutionDefines.targets')" />

In Solution1\SolutionDefines.targets add:

<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup>
        <DefineConstants>$(DefineConstants);TRACING_BUILD</DefineConstants>
    </PropertyGroup>
</Project>

In Solution2\SolutionDefines.targets add:

<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup>
        <DefineConstants>$(DefineConstants);ANOTHER_DEFINE</DefineConstants>
    </PropertyGroup>
</Project>

In this case you have:

For Solution1 - all projects have TRACING_BUILD define added

For Solution2 - all projects have ANOTHER_DEFINE define added

For Solution3 - all projects - no defines added

In this approach you must store all solutions with solution wide defines in separate directories

Answer 3

Years later, and similar to Alexei's answer but supported innately.

One can make a Directory.Build.props similar to a NuGet.Config file as per

https://learn.microsoft.com/en-us/visualstudio/msbuild/customize-your-build?view=vs-2019

Ours looks like:

<Project>
    <PropertyGroup>
        <DefineConstants>RC_427</DefineConstants>
    </PropertyGroup>
</Project>

And it effectively includes this into all CSPROJ files in your SLN. For some reason that particular solution is insanely hard to find via google. Been around since MSBuild 15

Answer 4

I don't think there is a way to create a solution-wide #define. You can create one for each project/assembly, as the other answers have described, but you'll need to do this for each and every project in the solution if you need all source code files to know of that #define.

Answer 5

To expand on the answers @Murtago and @Mark Cidade to make it solution wide:

Open the configuration manager for the solution and create a new configuration (copied from the closest match) then change conditional symbols for the projects that need different ones.

Answer 6

In case you have both C# and C++ projects in the solution and need to share preprocessor definitions among them. Create some SolutionDefines.targets file near your *.sln as follows

<?xml version="1.0" encoding="utf-8"?>
<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup>
        <DefineConstants>$(DefineConstants);MY_DEFINITION</DefineConstants>
    </PropertyGroup>
  <ItemDefinitionGroup>
    <ClCompile>
      <PreprocessorDefinitions>MY_DEFINITION;%(PreprocessorDefinitions)</PreprocessorDefinitions>
    </ClCompile>
  </ItemDefinitionGroup>
</Project>

Then add to C/C++/C# *.vcproj/*.vcxproj/*.csproj project files this line somewhere in the end

<Import Project="$(SolutionDir)SolutionDefines.targets" Condition="exists('$(SolutionDir)SolutionDefines.targets')" />

Ok, now you can enjoy #if MY_DEFINITION in C# and #ifdef MY_DEFINITION in C/C++. Visual Studio C# editor doesn't like this way and tells there is no MY_DEFINITION defined. But, C# compiler csc.exe gets the symbol properly.

Answer 7

There is one more workaround, correct me if i'm wrong:

For example, ProjectA references ProjectB, and ProjectsCommon contains base static variable. Both projects refernece ProjectsCommon.

Code in ProjectsCommon:

[assembly: InternalsVisibleTo("ProjectA")]

------------------------------------------

public class ConditionVariables
{
    public static bool IsABC { get; internal set; } = false;
}

Code in ProjectA:

#if ABC
    ProjectsCommon.ConditionVariables.IsABC = true;
#endif

Code in ProjectB:

if (ProjectsCommon.ConditionVariables.IsABC )
{
    // first scenario
}
else
{
    // second one
}

However, code in ProjectA should run first. This is probably good when ProjectA is a bootstarapper project.

Answer 8

in vs 2013 you can use /define:x or /d:x http://msdn.microsoft.com/en-us/library/0feaad6z.aspx

Answer 9

Create a new solution configuration in Configuration Manager and make sure that the box is checked to create new project configurations as well. And then in the Build properties of each project enter MONO into the Conditional compilation symbols box.

Answer 10

The proper place for a pre-processor directive is the VS build configuration. If you are using a command line to build your solution you can also pass it using /define option.

Answer 11

I don't know of a solution wide definition, but I was able to quickly add a preprocessor definition to all projects by doing the following:

1. hold ctrl and select each project
2. right click on any selected project and choose Properties
3. go to C/C++ --> Preprocessor
4. click the little down arrow beside Preprocessor Definitions
5. choose <Edit...>
6. add my definition after <different options>
7. OK out of the menus

I'm using Visual Studio Community 2019 with a C code base.