How to Set Path Environment Variable using CMake a

问题:

I am using CMake to generate Visual Studio project files. I want to run the test executable after setting the PATH environment variable so that it is able to load the required dll. I tried as per the discussion at http://www.mail-archive.com/[e-mail]/msg21493.html but it does not work.

Have you used CMake with Visual Studio for this purpose? Please share your experiences.

Also, I find no easy way to debug my CMake script, for example to see what value it assigns to the PATH variable. Setting CMake verbose with CMAKE_VERBOSE_MAKEFILE does not help. How would I go about debugging it myself?

回答1:

For setting custom project setting in Visual Studio from CMake you can use a XML file as a template which can be configured from CMake to work as the .user file.
At my work we use this to set custom debug parameters.

Check the directory containing the generated .vcproj files for the user settings in the .user files. Here is a snippet of an example UserTemplate.vcproj file we use.

<?xml version="1.0" encoding="Windows-1252"?>
  <VisualStudioUserFile
    ProjectType="Visual C++"
    Version="9.00"
    ShowAllFiles="false"
    >
    <Configurations>
        <Configuration
            Name="Debug|@USERFILE_PLATFORM@"
            >
            <DebugSettings
                Command="@USERFILE_COMMAND_DEBUG@"
                WorkingDirectory="@USERFILE_WORKING_DIRECTORY_DEBUG@"
                CommandArguments="@USERFILE_COMMAND_ARGUMENTS_DEBUG@"
                Attach="false"
                DebuggerType="3"
                Remote="1"
                RemoteMachine="@USERFILE_REMOTE_MACHINE_DEBUG@"
                            <!-- More settings removed for snippet -->
            />
        </Configuration>
            <!-- Rest of Configurations -->

This way you can inject any needed variables from CMake into the .user file. In CMake you can set the appropiate CMake variables (and add more in the template file if you need them). Next you can do something like this to configure the file.

# Find user and system name
SET(SYSTEM_NAME $ENV{USERDOMAIN} CACHE STRING SystemName)
SET(USER_NAME $ENV{USERNAME} CACHE STRING UserName)

# Configure the template file
SET(USER_FILE ${_projectName}.vcproj.${SYSTEM_NAME}.${USER_NAME}.user)
SET(OUTPUT_PATH ${CMAKE_CURRENT_BINARY_DIR}/${USER_FILE})
CONFIGURE_FILE(UserTemplate.user ${USER_FILE} @ONLY)

回答2:

Just spotted this question now. To debug cmake files I use

MESSAGE( STATUS "static text ${variable}" )

I have never had to set the path get my tests to run. Are you using CTest? It looks like the link you are following is used with ctest.

If I was trying to get this to work I would use set_tests_properties explicitly first.

set_tests_properties(SomeTest PROPERTIES ENVIRONMENT "PATH=c:\somedir;c:\otherdir")

Then make it more general.

回答3:

Here is related CMake feature request report:

http://www.kwwidgets.org/Bug/view.php?id=8884

UPDATE: Solved as per Set Visual Studio project "custom environment variables" setting with CMake - thanks to Florian for the comment below.

回答4:

You can give any options globally with the new VS_USER_PROPS target property (version >= 3.8).

Here is a working example:

CMakeLists.txt

cmake_minimum_required(VERSION 3.0)

project(SetEnvPathTest)

file(WRITE main.cpp [=[
// http://en.cppreference.com/w/cpp/utility/program/getenv
#include <iostream>
#include <cstdlib>

int main()
{
    if(const char* env_p = std::getenv("PATH"))
        std::cout << "Your PATH is: " << env_p << '\n';
}
]=])
add_executable(${PROJECT_NAME} main.cpp)

file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}.Cpp.user.props" [=[
<?xml version="1.0" encoding="utf-8"?> 
<Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <LocalDebuggerEnvironment>PATH=C:\Test</LocalDebuggerEnvironment>
  </PropertyGroup>
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
    <LocalDebuggerEnvironment>PATH=C:\Test</LocalDebuggerEnvironment>
  </PropertyGroup>
</Project>
]=])

set_target_properties(
    ${PROJECT_NAME}
    PROPERTIES
        VS_USER_PROPS "${PROJECT_NAME}.Cpp.user.props"
) 

References

• CMake Issue #8884: Set Visual Studio project "custom environment variables" setting with CMake
• set diagnostics:caret from CMakeLists.txt

回答5:

Just wanted to point out that a very useful addition that allows you to set up multiple environment variables as opposed to only one (e.g., only PATH) is given in this link https://stackoverflow.com/a/40531167/9253113

For example, if in addition to setting PATH you wanted to set another variable OTHERVAR one would have to modify the line

<LocalDebuggerEnvironment>PATH=C:\Test</LocalDebuggerEnvironment>

to

<LocalDebuggerEnvironment>PATH=C:\Test &#xA;OTHERVAR="value of OTHERVAR"</LocalDebuggerEnvironment>

Where the symbol "
" tells the xml parser to introduce the LF character. So multiple variable definitions are possible if separated by the LF character (also the CR character works but NOT the combination CRLF)

Also notice that there CANNOT be any space between 
 and the next variable.