I’m not very familiar w/ cmake or vcpkg, but I’ve been assigned to work on a task to build some libraries using a tool which wraps the latter.

My goal, in the interests of perhaps helping me solve this XY problem, is to follow the directions from https://unicode-org.github.io/icu/userguide/icu4c/build.html#how-to-build-and-install-on-windows-with-cygwin, which tell you to run vcvars<ARCH>.bat before running configure.

My constraint is that I have to implement the build process from within a vcpkg ‘port’ .cmake file, so I can’t simply CALL the batch file directly to affect vcpkg/cmake’s environment.

My idea was to run another shell script which runs vcvars<ARCH>.bat & then echo the relevant details to stdout, and to have cmake parse that output & explicitly set the environment based on that.

My new script which implements that idea, called GetVCVars.bat looks like

@ECHO off

REM Run the VS batch script (the path to which should be the first & only parameter provided to this script) to set up the environment
CALL %* >NUL
IF ERRORLEVEL 1 (
ECHO %* failed with error %ERRORLEVEL% 1>&2
EXIT /B 1
)

REM Print out the relevant environment variables to stdout
SET | FINDSTR /R /X /C:"PATH=.*" /C:"INCLUDE=.*" /C:"LIB=.*" /C:"LIBPATH=.*" /C:"PLATFORM=.*" /C:"VS[0-9]*COMNTOOLS=.*"
EXIT /B 0

The relevant fragment of associated cmake logic is

# Output is of the form of key=value, one variable per line
set(VCVARS_SCRIPT "${VCVARS_SCRIPT_DIR}/../../../../../../Auxiliary/Build/vcvars${SIMBA_TARGET_BITNESS}.bat")
vcpkg_execute_required_process(
  COMMAND cmd /c GetVCVars.bat "${VCVARS_SCRIPT}"
  WORKING_DIRECTORY ${CURRENT_PORT_DIR}
  LOGNAME GetVCVars-${TARGET_TRIPLET}-${VCPKG_BUILD_TYPE}
  OUTPUT_VARIABLE VC_VARS
)

message(STATUS "VC_VARS = '${VC_VARS}'")

# Iterate over each line/variable definition
string(REGEX MATCHALL "[^rn]+" VC_VAR_DEFS "${VC_VARS}")
foreach(VC_VAR_DEF IN LISTS VC_VAR_DEFS)
  if(NOT ${VC_VAR_DEF} MATCHES "^([^=]+)=(.*)$")
    message(FATAL_ERROR "Unexpected line returned from GetVCVars.bat: ${VC_VAR_DEF}")
  endif()
  
  message(STATUS "Setting '${CMAKE_MATCH_1}' to '${CMAKE_MATCH_2}'")
  set(ENV{${CMAKE_MATCH_1}} ${CMAKE_MATCH_2})
endforeach()

The weird thing is, that when I test this, that I get the output -- VC_VARS = '' (Which I interpret to mean that the output variable I told vcpkg_execute_required_process to fill w/ the stdout of the invoked command was either not set, or set to an empty string???), even though a file called GetVCVars-build_configuration-release-out.log gets created with the content

INCLUDE=C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519include;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519ATLMFCinclude;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCAuxiliaryVSinclude;C:Program Files (x86)Windows Kits10include10.0.22621.0ucrt;C:Program Files (x86)Windows Kits10\include10.0.22621.0\um;C:Program Files (x86)Windows Kits10\include10.0.22621.0\shared;C:Program Files (x86)Windows Kits10\include10.0.22621.0\winrt;C:Program Files (x86)Windows Kits10\include10.0.22621.0\cppwinrt;C:Program Files (x86)Windows KitsNETFXSDK4.8includeum;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519include;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519ATLMFCinclude;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCAuxiliaryVSinclude;C:Program Files (x86)Windows Kits10include10.0.22621.0ucrt;C:Program Files (x86)Windows Kits10\include10.0.22621.0\um;C:Program Files (x86)Windows Kits10\include10.0.22621.0\shared;C:Program Files (x86)Windows Kits10\include10.0.22621.0\winrt;C:Program Files (x86)Windows Kits10\include10.0.22621.0\cppwinrt;C:Program Files (x86)Windows KitsNETFXSDK4.8includeum
LIB=C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519ATLMFClibx64;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519libx64;C:Program Files (x86)Windows KitsNETFXSDK4.8libumx64;C:Program Files (x86)Windows Kits10lib10.0.22621.0ucrtx64;C:Program Files (x86)Windows Kits10\lib10.0.22621.0\umx64;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519ATLMFClibx64;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519libx64;C:Program Files (x86)Windows KitsNETFXSDK4.8libumx64;C:Program Files (x86)Windows Kits10lib10.0.22621.0ucrtx64;C:Program Files (x86)Windows Kits10\lib10.0.22621.0\umx64
LIBPATH=C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519ATLMFClibx64;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519libx64;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519libx86storereferences;C:Program Files (x86)Windows Kits10UnionMetadata10.0.22621.0;C:Program Files (x86)Windows Kits10References10.0.22621.0;C:WINDOWSMicrosoft.NETFramework64v4.0.30319;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519ATLMFClibx64;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519libx64;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519libx86storereferences;C:Program Files (x86)Windows Kits10UnionMetadata10.0.22621.0;C:Program Files (x86)Windows Kits10References10.0.22621.0;C:WINDOWSMicrosoft.NETFramework64v4.0.30319
VS170COMNTOOLS=C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7Tools
PATH=C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519binHostX64x64;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDEVCVCPackages;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDECommonExtensionsMicrosoftTestWindow;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDECommonExtensionsMicrosoftTeamFoundationTeam Explorer;C:Program FilesMicrosoft Visual Studio2022EnterpriseMSBuildCurrentbinRoslyn;C:Program Files (x86)Microsoft Visual StudioSharedCommonVSPerfCollectionToolsvs2019\x64;C:Program Files (x86)Microsoft Visual StudioSharedCommonVSPerfCollectionToolsvs2019;C:Program Files (x86)Microsoft SDKsWindowsv10.0AbinNETFX 4.8 Toolsx64;C:Program Files (x86)HTML Help Workshop;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDECommonExtensionsMicrosoftFSharpTools;C:Program FilesMicrosoft Visual Studio2022EnterpriseTeam ToolsDiagnosticsHubCollector;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDEExtensionsMicrosoftCodeCoverage.Console;C:Program Files (x86)Windows Kits10bin10.0.22621.0\x64;C:Program Files (x86)Windows Kits10bin\x64;C:Program FilesMicrosoft Visual Studio2022Enterprise\MSBuildCurrentBinamd64;C:WINDOWSMicrosoft.NETFramework64v4.0.30319;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDE;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7Tools;C:/bitbucket/packagey/vcpkg/downloads/tools/python/python-3.11.5-x64;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCToolsMSVC14.39.33519binHostX64x64;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDEVCVCPackages;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDECommonExtensionsMicrosoftTestWindow;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDECommonExtensionsMicrosoftTeamFoundationTeam Explorer;C:Program FilesMicrosoft Visual Studio2022EnterpriseMSBuildCurrentbinRoslyn;C:Program Files (x86)Microsoft Visual StudioSharedCommonVSPerfCollectionToolsvs2019\x64;C:Program Files (x86)Microsoft Visual StudioSharedCommonVSPerfCollectionToolsvs2019;C:Program Files (x86)Microsoft SDKsWindowsv10.0AbinNETFX 4.8 Toolsx64;C:Program Files (x86)HTML Help Workshop;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDECommonExtensionsMicrosoftFSharpTools;C:Program FilesMicrosoft Visual Studio2022EnterpriseTeam ToolsDiagnosticsHubCollector;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDEExtensionsMicrosoftCodeCoverage.Console;C:Program Files (x86)Windows Kits10bin10.0.22621.0\x64;C:Program Files (x86)Windows Kits10bin\x64;C:Program FilesMicrosoft Visual Studio2022Enterprise\MSBuildCurrentBinamd64;C:WINDOWSMicrosoft.NETFramework64v4.0.30319;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDE;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7Tools;C:bitbucketpackageyvcpkgdownloadstoolspowershell-core-7.2.16-windows;C:Program FilesOpenLogicjdk-11.0.21.9-hotspotbin;C:Program FilesOpenLogicjdk-8.0.392.08-hotspotbin;C:Program FilesPython312Scripts;C:Program FilesPython312;C:Program FilesEclipse Adoptiumjdk-11.0.21.9-hotspotbin;C:Program FilesEclipse Adoptiumjdk-17.0.8.101-hotspotbin;C:Program Files (x86)Eclipse Adoptiumjdk-8.0.392.8-hotspotbin;C:Program FilesEclipse Adoptiumjdk-8.0.392.8-hotspotbin;C:Program FilesEclipse Adoptiumjre-8.0.392.8-hotspotbin;C:Program FilesEclipse Adoptiumjre-17.0.8.101-hotspotbin;C:Program FilesEclipse Adoptiumjre-11.0.21.9-hotspotbin;C:Program Files (x86)Eclipse Adoptiumjre-8.0.392.8-hotspotbin;C:WINDOWSsystem32;C:WINDOWS;C:WINDOWSSystem32Wbem;C:WINDOWSSystem32WindowsPowerShellv1.0;C:WINDOWSSystem32OpenSSH;C:Program Filesdotnet;C:Program FilesPerforce;C:Program FilesMicrosoft SQL Server120ToolsBinn;C:Program FilesMicrosoft SQL Server130ToolsBinn;C:Program FilesMicrosoft SQL Server150ToolsBinn;C:Program FilesPuTTY;C:Strawberrycbin;C:Strawberryperlsitebin;C:Strawberryperlbin;C:Program Files (x86)Windows Kits10Windows Performance Toolkit;C:Program Files (x86)Windows Kits10Microsoft Application VirtualizationSequencer;C:Program FilesGitcmd;C:Program FilesAmazonAWSCLIV2;C:Usersmatthew.wozniczkaAppDataLocalMicrosoftWindowsApps;C:ripgrep-13.0.0-i686-pc-windows-msvc;C:Program FilesOpenLogicjdk-11.0.21.9-hotspotbinserver;C:Usersmatthew.wozniczka.dotnettools;C:Program Files (x86)Dr. Memorybin;C:Usersmatthew.wozniczkaAppDataLocalProgramsMicrosoft VS Codebin;C:Usersmatthew.wozniczkaAppDataLocalGitHubDesktopbin;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDECommonExtensionsMicrosoftCMakeCMakebin;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDECommonExtensionsMicrosoftCMakeNinja;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDEVCLinuxbinConnectionManagerExe;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCvcpkg;C:/bitbucket/packagey/vcpkg/downloads/tools/ninja/1.10.2-windows;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDECommonExtensionsMicrosoftCMakeCMakebin;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDECommonExtensionsMicrosoftCMakeNinja;C:Program FilesMicrosoft Visual Studio2022EnterpriseCommon7IDEVCLinuxbinConnectionManagerExe;C:Program FilesMicrosoft Visual Studio2022EnterpriseVCvcpkg

(i.e. what I expected)

I don’t understand what I’ve done wrong (https://learn.microsoft.com/en-us/vcpkg/maintainers/functions/vcpkg_execute_required_process#output_variable)?