Visual Studio: Allow setting Single Byte Character Set (#12189)

For Visual Studio using the Preprocessor Define _SBCS. This behavior
is similar to the way that _UNICODE and _MBCS work already.

Added tests to confirm this behavior.

Source/cmLocalVisualStudio7Generator.cxx

@@ -774,6 +774,10 @@ void cmLocalVisualStudio7Generator::WriteConfiguration(std::ostream& fout,
     {
     fout << "\t\t\tCharacterSet=\"1\">\n";
     }
+  else if(targetOptions.UsingSBCS())
+    {
+    fout << "\t\t\tCharacterSet=\"0\">\n";
+    }
   else
     {
     fout << "\t\t\tCharacterSet=\"2\">\n";

Source/cmVisualStudio10TargetGenerator.cxx

@@ -394,6 +394,11 @@ void cmVisualStudio10TargetGenerator::WriteProjectConfigurationValues()
       {
       this->WriteString("<CharacterSet>Unicode</CharacterSet>\n", 2);
       }
+    else if (this->Target->GetType() <= cmTarget::MODULE_LIBRARY &&
+       this->ClOptions[*i]->UsingSBCS())
+      {
+      this->WriteString("<CharacterSet>NotSet</CharacterSet>\n", 2);
+      }
     else
       {
       this->WriteString("<CharacterSet>MultiByte</CharacterSet>\n", 2);

Source/cmVisualStudioGeneratorOptions.cxx

@@ -117,6 +117,20 @@ bool cmVisualStudioGeneratorOptions::UsingUnicode()
     }
   return false;
 }
+//----------------------------------------------------------------------------
+bool cmVisualStudioGeneratorOptions::UsingSBCS()
+{
+  // Look for the a _SBCS definition.
+  for(std::vector<std::string>::const_iterator di = this->Defines.begin();
+      di != this->Defines.end(); ++di)
+    {
+    if(*di == "_SBCS")
+      {
+      return true;
+      }
+    }
+  return false;
+}
 
 //----------------------------------------------------------------------------
 void cmVisualStudioGeneratorOptions::Parse(const char* flags)

Source/cmVisualStudioGeneratorOptions.h

@@ -48,6 +48,7 @@ public:
 
   // Check for specific options.
   bool UsingUnicode();
+  bool UsingSBCS();
 
   bool IsDebug();
   // Write options to output.

Tests/CMakeLists.txt

@@ -1306,6 +1306,8 @@ ${CMake_BINARY_DIR}/bin/cmake -DVERSION=master -P ${CMake_SOURCE_DIR}/Utilities/
   endif()
 
   IF(${CMAKE_TEST_GENERATOR} MATCHES "Visual Studio")
+    ADD_TEST_MACRO(SBCS SBCS)
+
     ADD_TEST(VSExternalInclude ${CMAKE_CTEST_COMMAND}
       --build-and-test
       "${CMake_SOURCE_DIR}/Tests/VSExternalInclude"

Tests/SBCS/CMakeLists.txt

@@ -0,0 +1,6 @@
+# a SBCS test case
+project (SBCS)
+
+add_definitions(-D_SBCS)
+
+add_executable (SBCS SBCS.cxx)

Tests/SBCS/SBCS.cxx

@@ -0,0 +1,22 @@
+// Test to verify that _SBCS being defined causes CharacterSet to be set to 0 (Single Byte Character Set)
+
+int main ()
+{
+#ifdef _UNICODE
+  bool UnicodeSet=true;
+#else
+  bool UnicodeSet=false;
+#endif
+
+#ifdef _MBCS
+  bool MBCSSet=true;
+#else
+  bool MBCSSet=false;
+#endif
+
+  // if neither _UNICODE nor _MBCS is set, CharacterSet must be set to SBCS.
+  bool SBCSSet=(!UnicodeSet && !MBCSSet);
+
+  // Reverse boolean to indicate error case correctly
+  return !SBCSSet;
+}