From 078b88a11abe97766824a0f0e712fa876bbb08b4 Mon Sep 17 00:00:00 2001
From: Fredrik Roubert <roubert@google.com>
Date: Wed, 3 Jan 2024 11:42:30 +0900
Subject: [PATCH] ICU-21107 Specify language standard versions C11 & C++17 also
 for MSVC.

There were until now no versions specified at all, relying on the
default (or commandline overrides) to be sufficiently recent.
---
 icu4c/source/common/common.vcxproj                 |  2 ++
 icu4c/source/common/common_uwp.vcxproj             |  2 ++
 icu4c/source/extra/uconv/uconv.vcxproj             |  4 +++-
 icu4c/source/i18n/i18n.vcxproj                     |  2 ++
 icu4c/source/i18n/i18n_uwp.vcxproj                 |  2 ++
 icu4c/source/io/io.vcxproj                         |  2 ++
 icu4c/source/layoutex/layoutex.vcxproj             |  2 ++
 icu4c/source/samples/break/break.vcxproj           |  2 ++
 icu4c/source/samples/cal/cal.vcxproj               |  2 ++
 icu4c/source/samples/case/case.vcxproj             |  4 +++-
 icu4c/source/samples/citer/citer.vcxproj           |  6 ++++++
 icu4c/source/samples/coll/coll.vcxproj             |  6 ++++++
 icu4c/source/samples/csdet/csdet.vcxproj           |  6 ++++++
 icu4c/source/samples/date/date.vcxproj             |  6 ++++++
 icu4c/source/samples/datefmt/datefmt.vcxproj       |  6 ++++++
 .../samples/dtitvfmtsample/dtitvfmtsample.vcxproj  |  6 ++++++
 .../samples/dtptngsample/dtptngsample.vcxproj      |  6 ++++++
 icu4c/source/samples/layout/layout.vcxproj         |  6 ++++++
 icu4c/source/samples/legacy/legacy.vcxproj         |  6 ++++++
 icu4c/source/samples/msgfmt/msgfmt.vcxproj         |  6 ++++++
 icu4c/source/samples/numfmt/numfmt.vcxproj         |  6 ++++++
 .../samples/plurfmtsample/plurfmtsample.vcxproj    |  6 ++++++
 icu4c/source/samples/props/props.vcxproj           |  6 ++++++
 icu4c/source/samples/strsrch/strsrch.vcxproj       |  6 ++++++
 icu4c/source/samples/translit/translit.vcxproj     |  2 ++
 icu4c/source/samples/uciter8/uciter8.vcxproj       |  2 ++
 icu4c/source/samples/ucnv/ucnv.vcxproj             |  2 ++
 icu4c/source/samples/udata/reader.vcxproj          |  6 ++++++
 icu4c/source/samples/udata/writer.vcxproj          |  6 ++++++
 icu4c/source/samples/ufortune/ufortune.vcxproj     |  2 ++
 icu4c/source/samples/ugrep/ugrep.vcxproj           |  6 ++++++
 icu4c/source/samples/uresb/uresb.vcxproj           |  2 ++
 icu4c/source/samples/ustring/ustring.vcxproj       |  2 ++
 icu4c/source/stubdata/stubdata.vcxproj             |  4 +++-
 icu4c/source/test/cintltst/cintltst.vcxproj        |  2 ++
 icu4c/source/test/intltest/intltest.vcxproj        |  2 ++
 icu4c/source/test/iotest/iotest.vcxproj            |  4 +++-
 icu4c/source/test/letest/cletest.vcxproj           |  6 ++++++
 icu4c/source/test/letest/gendata.vcxproj           |  6 ++++++
 icu4c/source/test/letest/letest.vcxproj            |  6 ++++++
 .../test/perf/DateFmtPerf/DateFmtPerf.vcxproj      |  6 ++++++
 icu4c/source/test/perf/charperf/charperf.vcxproj   |  6 ++++++
 icu4c/source/test/perf/collperf/collperf.vcxproj   |  6 ++++++
 icu4c/source/test/perf/collperf2/collperf2.vcxproj |  6 ++++++
 icu4c/source/test/perf/convperf/convperf.vcxproj   |  6 ++++++
 .../source/test/perf/normperf/dtfmtrtperf.vcxproj  |  6 ++++++
 icu4c/source/test/perf/normperf/normperf.vcxproj   |  6 ++++++
 .../test/perf/strsrchperf/strsrchperf.vcxproj      |  6 ++++++
 icu4c/source/test/perf/ubrkperf/ubrkperf.vcxproj   |  6 ++++++
 .../test/perf/ucnvavailperf/ucnvavailperf.vcxproj  |  6 ++++++
 .../source/test/perf/unisetperf/unisetperf.vcxproj |  6 ++++++
 icu4c/source/test/perf/usetperf/usetperf.vcxproj   |  6 ++++++
 icu4c/source/test/perf/ustrperf/stringperf.vcxproj |  6 ++++++
 icu4c/source/test/perf/utfperf/utfperf.vcxproj     |  6 ++++++
 .../source/test/perf/utrie2perf/utrie2perf.vcxproj |  6 ++++++
 icu4c/source/tools/ctestfw/ctestfw.vcxproj         |  4 +++-
 icu4c/source/tools/genbrk/genbrk.vcxproj           |  2 ++
 icu4c/source/tools/genccode/genccode.vcxproj       |  2 ++
 icu4c/source/tools/gencfu/gencfu.vcxproj           |  2 ++
 icu4c/source/tools/gencmn/gencmn.vcxproj           |  4 +++-
 icu4c/source/tools/gencnval/gencnval.vcxproj       |  2 ++
 icu4c/source/tools/gendict/gendict.vcxproj         |  4 +++-
 icu4c/source/tools/gennorm2/gennorm2.vcxproj       |  2 ++
 icu4c/source/tools/genrb/derb.vcxproj              |  4 +++-
 icu4c/source/tools/genrb/genrb.vcxproj             |  4 +++-
 icu4c/source/tools/gensprep/gensprep.vcxproj       |  2 ++
 icu4c/source/tools/gentest/gentest.vcxproj         |  4 +++-
 .../tools/icuexportdata/icuexportdata.vcxproj      |  2 ++
 icu4c/source/tools/icuinfo/icuinfo.vcxproj         |  2 ++
 icu4c/source/tools/icuinfo/testplug.vcxproj        |  4 +++-
 icu4c/source/tools/icupkg/icupkg.vcxproj           |  4 +++-
 icu4c/source/tools/icuswap/icuswap.vcxproj         | 14 ++++++++++----
 icu4c/source/tools/makeconv/makeconv.vcxproj       |  2 ++
 icu4c/source/tools/pkgdata/pkgdata.vcxproj         |  4 +++-
 icu4c/source/tools/toolutil/toolutil.vcxproj       |  4 +++-
 icu4c/source/tools/tzcode/icuzdump.vcxproj         |  8 +++++++-
 76 files changed, 319 insertions(+), 19 deletions(-)

diff --git a/icu4c/source/common/common.vcxproj b/icu4c/source/common/common.vcxproj
index be3093bd9392..56fe146ed7ae 100644
--- a/icu4c/source/common/common.vcxproj
+++ b/icu4c/source/common/common.vcxproj
@@ -34,6 +34,8 @@
       <TypeLibraryName>$(OutDir)\icuuc.tlb</TypeLibraryName>
     </Midl>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
       <PreprocessorDefinitions>U_ATTRIBUTE_DEPRECATED=;U_COMMON_IMPLEMENTATION;U_PLATFORM_USES_ONLY_WIN32_API=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <DisableLanguageExtensions>false</DisableLanguageExtensions>
       <WarningLevel>Level3</WarningLevel>
diff --git a/icu4c/source/common/common_uwp.vcxproj b/icu4c/source/common/common_uwp.vcxproj
index b40f65c52726..7379eade57fb 100644
--- a/icu4c/source/common/common_uwp.vcxproj
+++ b/icu4c/source/common/common_uwp.vcxproj
@@ -72,6 +72,8 @@
       <TypeLibraryName>$(OutDir)\icuuc.tlb</TypeLibraryName>
     </Midl>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
       <AdditionalIncludeDirectories>..\..\include;..\common;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <!-- U_DISABLE_RENAMING -->
       <!-- U_HIDE_DRAFT_API & U_HIDE_DEPRECATED_API -->
diff --git a/icu4c/source/extra/uconv/uconv.vcxproj b/icu4c/source/extra/uconv/uconv.vcxproj
index e00a288f4d38..adfe06c87d3e 100644
--- a/icu4c/source/extra/uconv/uconv.vcxproj
+++ b/icu4c/source/extra/uconv/uconv.vcxproj
@@ -34,9 +34,11 @@
       <TypeLibraryName>$(OutDir)\uconv.tlb</TypeLibraryName>
     </Midl>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
       <WarningLevel>Level3</WarningLevel>
       <CompileAs>Default</CompileAs>
-      <DisableLanguageExtensions>true</DisableLanguageExtensions>
+      <DisableLanguageExtensions>false</DisableLanguageExtensions>
       <AdditionalIncludeDirectories>..\..\..\include;..\..\common;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>UCONVMSG_LINK;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <PrecompiledHeaderOutputFile>$(OutDir)\uconv.pch</PrecompiledHeaderOutputFile>
diff --git a/icu4c/source/i18n/i18n.vcxproj b/icu4c/source/i18n/i18n.vcxproj
index 73ab2d4651e6..a9622aa45e95 100644
--- a/icu4c/source/i18n/i18n.vcxproj
+++ b/icu4c/source/i18n/i18n.vcxproj
@@ -34,6 +34,8 @@
       <TypeLibraryName>$(OutDir)\icuin.tlb</TypeLibraryName>
     </Midl>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
       <PreprocessorDefinitions>U_ATTRIBUTE_DEPRECATED=;U_I18N_IMPLEMENTATION;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <DisableLanguageExtensions>false</DisableLanguageExtensions>
       <WarningLevel>Level3</WarningLevel>
diff --git a/icu4c/source/i18n/i18n_uwp.vcxproj b/icu4c/source/i18n/i18n_uwp.vcxproj
index 9afcb5ddb940..f389562d0580 100644
--- a/icu4c/source/i18n/i18n_uwp.vcxproj
+++ b/icu4c/source/i18n/i18n_uwp.vcxproj
@@ -70,6 +70,8 @@
       <SuppressStartupBanner>true</SuppressStartupBanner>
     </Midl>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
       <AdditionalIncludeDirectories>..\..\include;..\common;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <!-- U_DISABLE_RENAMING -->
       <!-- U_HIDE_DRAFT_API & U_HIDE_DEPRECATED_API -->
diff --git a/icu4c/source/io/io.vcxproj b/icu4c/source/io/io.vcxproj
index ff3485fd4dc5..bad5d666ebd9 100644
--- a/icu4c/source/io/io.vcxproj
+++ b/icu4c/source/io/io.vcxproj
@@ -34,6 +34,8 @@
       <TypeLibraryName>$(OutDir)\icuio.tlb</TypeLibraryName>
     </Midl>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
       <AdditionalIncludeDirectories>..\..\include;..\common;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>U_IO_IMPLEMENTATION;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <DisableLanguageExtensions>false</DisableLanguageExtensions>
diff --git a/icu4c/source/layoutex/layoutex.vcxproj b/icu4c/source/layoutex/layoutex.vcxproj
index ba548fc33eae..0445eeed7488 100644
--- a/icu4c/source/layoutex/layoutex.vcxproj
+++ b/icu4c/source/layoutex/layoutex.vcxproj
@@ -34,6 +34,8 @@
     <!-- Options that are common to *all* project configurations -->
   <ItemDefinitionGroup>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
       <AdditionalIncludeDirectories>..\..\include;..\common;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>U_LAYOUTEX_IMPLEMENTATION;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <WarningLevel>Level3</WarningLevel>
diff --git a/icu4c/source/samples/break/break.vcxproj b/icu4c/source/samples/break/break.vcxproj
index d9a51001d2af..59a93b56ed3f 100644
--- a/icu4c/source/samples/break/break.vcxproj
+++ b/icu4c/source/samples/break/break.vcxproj
@@ -33,6 +33,8 @@
   <!-- Options that are common to *all* project configurations -->
   <ItemDefinitionGroup>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
       <AdditionalIncludeDirectories>..\..\..\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <WarningLevel>Level3</WarningLevel>
     </ClCompile>
diff --git a/icu4c/source/samples/cal/cal.vcxproj b/icu4c/source/samples/cal/cal.vcxproj
index 51f721b60806..aee2c34333ca 100644
--- a/icu4c/source/samples/cal/cal.vcxproj
+++ b/icu4c/source/samples/cal/cal.vcxproj
@@ -33,6 +33,8 @@
   <!-- Options that are common to *all* project configurations -->
   <ItemDefinitionGroup>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
       <AdditionalIncludeDirectories>..\..\..\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <WarningLevel>Level3</WarningLevel>
       <DisableLanguageExtensions>false</DisableLanguageExtensions>
diff --git a/icu4c/source/samples/case/case.vcxproj b/icu4c/source/samples/case/case.vcxproj
index 38be307d6612..f0c4122e48c5 100644
--- a/icu4c/source/samples/case/case.vcxproj
+++ b/icu4c/source/samples/case/case.vcxproj
@@ -33,9 +33,11 @@
   <!-- Options that are common to *all* project configurations -->
   <ItemDefinitionGroup>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
       <AdditionalIncludeDirectories>..\..\..\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <WarningLevel>Level3</WarningLevel>
-      <DisableLanguageExtensions>true</DisableLanguageExtensions>
+      <DisableLanguageExtensions>false</DisableLanguageExtensions>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
diff --git a/icu4c/source/samples/citer/citer.vcxproj b/icu4c/source/samples/citer/citer.vcxproj
index c92114424495..68e4fadeb2fe 100644
--- a/icu4c/source/samples/citer/citer.vcxproj
+++ b/icu4c/source/samples/citer/citer.vcxproj
@@ -30,6 +30,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Release|x64'">.\x64\Release\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Release|x64'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <AdditionalIncludeDirectories>..\..\..\include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
diff --git a/icu4c/source/samples/coll/coll.vcxproj b/icu4c/source/samples/coll/coll.vcxproj
index fd49d1b89158..f58b05217150 100644
--- a/icu4c/source/samples/coll/coll.vcxproj
+++ b/icu4c/source/samples/coll/coll.vcxproj
@@ -30,6 +30,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">.\x64\Debug\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <Midl>
       <TypeLibraryName>.\x86\Release/coll.tlb</TypeLibraryName>
diff --git a/icu4c/source/samples/csdet/csdet.vcxproj b/icu4c/source/samples/csdet/csdet.vcxproj
index 234a7b84e687..74d4ad57dd1a 100644
--- a/icu4c/source/samples/csdet/csdet.vcxproj
+++ b/icu4c/source/samples/csdet/csdet.vcxproj
@@ -31,6 +31,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Release|x64'">.\x64\Release\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Release|x64'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <AdditionalIncludeDirectories>../../../include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
diff --git a/icu4c/source/samples/date/date.vcxproj b/icu4c/source/samples/date/date.vcxproj
index 3d20f9576edb..e5d34f373454 100644
--- a/icu4c/source/samples/date/date.vcxproj
+++ b/icu4c/source/samples/date/date.vcxproj
@@ -30,6 +30,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">.\x64\Debug\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <Midl>
       <TypeLibraryName>.\x86\Release/date.tlb</TypeLibraryName>
diff --git a/icu4c/source/samples/datefmt/datefmt.vcxproj b/icu4c/source/samples/datefmt/datefmt.vcxproj
index 00dcd6d6700f..b1cf597f7b90 100644
--- a/icu4c/source/samples/datefmt/datefmt.vcxproj
+++ b/icu4c/source/samples/datefmt/datefmt.vcxproj
@@ -30,6 +30,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Release|x64'">.\x64\Release\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Release|x64'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <Midl>
       <TypeLibraryName>.\x86\Debug/datefmt.tlb</TypeLibraryName>
diff --git a/icu4c/source/samples/dtitvfmtsample/dtitvfmtsample.vcxproj b/icu4c/source/samples/dtitvfmtsample/dtitvfmtsample.vcxproj
index aea18b217f37..e5fbcb88a2d1 100644
--- a/icu4c/source/samples/dtitvfmtsample/dtitvfmtsample.vcxproj
+++ b/icu4c/source/samples/dtitvfmtsample/dtitvfmtsample.vcxproj
@@ -65,6 +65,12 @@
     <IntDir>.\x64\Release\</IntDir>
     <TargetName>$(ProjectName)</TargetName>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <WarningLevel>Level3</WarningLevel>
diff --git a/icu4c/source/samples/dtptngsample/dtptngsample.vcxproj b/icu4c/source/samples/dtptngsample/dtptngsample.vcxproj
index 542b3439f03e..3d01f6cb4652 100644
--- a/icu4c/source/samples/dtptngsample/dtptngsample.vcxproj
+++ b/icu4c/source/samples/dtptngsample/dtptngsample.vcxproj
@@ -65,6 +65,12 @@
     <IntDir>.\x64\Release\</IntDir>
     <TargetName>$(ProjectName)</TargetName>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
       <WarningLevel>Level3</WarningLevel>
diff --git a/icu4c/source/samples/layout/layout.vcxproj b/icu4c/source/samples/layout/layout.vcxproj
index 31ac1d942ef4..66c6053cca7b 100644
--- a/icu4c/source/samples/layout/layout.vcxproj
+++ b/icu4c/source/samples/layout/layout.vcxproj
@@ -30,6 +30,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">.\x64\Debug\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <Midl>
       <TypeLibraryName>.\x86\Release/layout.tlb</TypeLibraryName>
diff --git a/icu4c/source/samples/legacy/legacy.vcxproj b/icu4c/source/samples/legacy/legacy.vcxproj
index 655a7cab41ed..1f7c71ac4385 100644
--- a/icu4c/source/samples/legacy/legacy.vcxproj
+++ b/icu4c/source/samples/legacy/legacy.vcxproj
@@ -66,6 +66,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">.\x64\Debug\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <Midl>
       <TypeLibraryName>.\x86\Release/legacy.tlb</TypeLibraryName>
diff --git a/icu4c/source/samples/msgfmt/msgfmt.vcxproj b/icu4c/source/samples/msgfmt/msgfmt.vcxproj
index b1a90405b6c2..1123d6fb545b 100644
--- a/icu4c/source/samples/msgfmt/msgfmt.vcxproj
+++ b/icu4c/source/samples/msgfmt/msgfmt.vcxproj
@@ -30,6 +30,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">.\x64\Debug\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <Midl>
       <TypeLibraryName>.\x86\Release/msgfmt.tlb</TypeLibraryName>
diff --git a/icu4c/source/samples/numfmt/numfmt.vcxproj b/icu4c/source/samples/numfmt/numfmt.vcxproj
index 4ea39eb54a74..3de1f6d1edc9 100644
--- a/icu4c/source/samples/numfmt/numfmt.vcxproj
+++ b/icu4c/source/samples/numfmt/numfmt.vcxproj
@@ -30,6 +30,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Release|x64'">.\x64\Release\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Release|x64'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <Midl>
       <TypeLibraryName>.\x86\Debug/numfmt.tlb</TypeLibraryName>
diff --git a/icu4c/source/samples/plurfmtsample/plurfmtsample.vcxproj b/icu4c/source/samples/plurfmtsample/plurfmtsample.vcxproj
index c0d3246ae82b..1b375dbceb94 100644
--- a/icu4c/source/samples/plurfmtsample/plurfmtsample.vcxproj
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@@ -35,6 +35,12 @@
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     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
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index c68b70066229..14e5afd7ffe8 100644
--- a/icu4c/source/test/perf/unisetperf/unisetperf.vcxproj
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@@ -63,6 +63,12 @@
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     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Release|x64'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
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   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
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diff --git a/icu4c/source/test/perf/usetperf/usetperf.vcxproj b/icu4c/source/test/perf/usetperf/usetperf.vcxproj
index 9c566432371f..5e8053573626 100644
--- a/icu4c/source/test/perf/usetperf/usetperf.vcxproj
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@@ -63,6 +63,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">.\x64\Debug\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <Midl>
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index 86dd1ae8342d..d32d34cc174a 100644
--- a/icu4c/source/test/perf/ustrperf/stringperf.vcxproj
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     <IntDir Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">.\x64\Debug\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <Midl>
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diff --git a/icu4c/source/test/perf/utfperf/utfperf.vcxproj b/icu4c/source/test/perf/utfperf/utfperf.vcxproj
index 49aea66a06fc..11261d667d44 100644
--- a/icu4c/source/test/perf/utfperf/utfperf.vcxproj
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@@ -63,6 +63,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Release|x64'">.\x64\Release\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Release|x64'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
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+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
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diff --git a/icu4c/source/test/perf/utrie2perf/utrie2perf.vcxproj b/icu4c/source/test/perf/utrie2perf/utrie2perf.vcxproj
index d829fcbd5bdb..a5735b1002b6 100644
--- a/icu4c/source/test/perf/utrie2perf/utrie2perf.vcxproj
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@@ -63,6 +63,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Release|x64'">.\x64\Release\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Release|x64'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
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index f55c3f0b0071..5e9770c702a4 100644
--- a/icu4c/source/tools/ctestfw/ctestfw.vcxproj
+++ b/icu4c/source/tools/ctestfw/ctestfw.vcxproj
@@ -32,9 +32,11 @@
       <TypeLibraryName>$(OutDir)/icutest.tlb</TypeLibraryName>
     </Midl>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
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       <PreprocessorDefinitions>T_CTEST_IMPLEMENTATION;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <DisableLanguageExtensions>true</DisableLanguageExtensions>
+      <DisableLanguageExtensions>false</DisableLanguageExtensions>
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       <CompileAs>Default</CompileAs>
       <PrecompiledHeaderOutputFile>$(OutDir)/icutest.pch</PrecompiledHeaderOutputFile>
diff --git a/icu4c/source/tools/genbrk/genbrk.vcxproj b/icu4c/source/tools/genbrk/genbrk.vcxproj
index 44cb00ed8f01..d384f10ec612 100644
--- a/icu4c/source/tools/genbrk/genbrk.vcxproj
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@@ -32,6 +32,8 @@
       <TypeLibraryName>$(OutDir)/genbrk.tlb</TypeLibraryName>
     </Midl>
     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
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diff --git a/icu4c/source/tools/genccode/genccode.vcxproj b/icu4c/source/tools/genccode/genccode.vcxproj
index aad028f8c710..413ba78813c5 100644
--- a/icu4c/source/tools/genccode/genccode.vcxproj
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@@ -32,6 +32,8 @@
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     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
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diff --git a/icu4c/source/tools/gencfu/gencfu.vcxproj b/icu4c/source/tools/gencfu/gencfu.vcxproj
index 4018d5078dad..87bb4d9d632a 100644
--- a/icu4c/source/tools/gencfu/gencfu.vcxproj
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@@ -32,6 +32,8 @@
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     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
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--- a/icu4c/source/tools/gencmn/gencmn.vcxproj
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@@ -32,9 +32,11 @@
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     <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
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--- a/icu4c/source/tools/gencnval/gencnval.vcxproj
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@@ -32,6 +32,8 @@
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     <ClCompile>
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--- a/icu4c/source/tools/gendict/gendict.vcxproj
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@@ -32,9 +32,11 @@
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     <ClCompile>
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+      <LanguageStandard_C>stdc11</LanguageStandard_C>
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index 2f41299098be..dcafdcda430b 100644
--- a/icu4c/source/tools/gennorm2/gennorm2.vcxproj
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@@ -47,6 +47,8 @@
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     <ClCompile>
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index f5ba9bf22f3f..833a42d8e736 100644
--- a/icu4c/source/tools/genrb/derb.vcxproj
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@@ -32,9 +32,11 @@
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--- a/icu4c/source/tools/genrb/genrb.vcxproj
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@@ -32,6 +32,8 @@
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@@ -33,9 +33,11 @@
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@@ -32,6 +32,8 @@
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@@ -32,6 +32,8 @@
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@@ -32,9 +32,11 @@
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+      <LanguageStandard_C>stdc11</LanguageStandard_C>
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--- a/icu4c/source/tools/icupkg/icupkg.vcxproj
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@@ -32,9 +32,11 @@
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+  <ItemDefinitionGroup>
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@@ -32,6 +32,8 @@
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index 0995ef06f7eb..529a03a6e4db 100644
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+      <AdditionalIncludeDirectories>..\..\..\include;..\..\common;..\..\i18n;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
       <PreprocessorDefinitions>U_TOOLUTIL_IMPLEMENTATION;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <DisableLanguageExtensions>false</DisableLanguageExtensions>
       <WarningLevel>Level3</WarningLevel>
diff --git a/icu4c/source/tools/tzcode/icuzdump.vcxproj b/icu4c/source/tools/tzcode/icuzdump.vcxproj
index 4f7b96fc2918..93bca180eb39 100644
--- a/icu4c/source/tools/tzcode/icuzdump.vcxproj
+++ b/icu4c/source/tools/tzcode/icuzdump.vcxproj
@@ -45,6 +45,12 @@
     <IntDir Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">$(Configuration)\</IntDir>
     <LinkIncremental Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">false</LinkIncremental>
   </PropertyGroup>
+  <ItemDefinitionGroup>
+    <ClCompile>
+      <LanguageStandard>stdcpp17</LanguageStandard>
+      <LanguageStandard_C>stdc11</LanguageStandard_C>
+    </ClCompile>
+  </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <CustomBuildStep>
       <Command>copy "$(TargetPath)" ..\..\..\bin
@@ -58,7 +64,7 @@
       <MinimalRebuild>false</MinimalRebuild>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
-      <DisableLanguageExtensions>true</DisableLanguageExtensions>
+      <DisableLanguageExtensions>false</DisableLanguageExtensions>
       <PrecompiledHeader>
       </PrecompiledHeader>
       <PrecompiledHeaderOutputFile>.\x86\Debug/icuzdump.pch</PrecompiledHeaderOutputFile>