VS2010 custom build tool for generating .h file

I'm trying to integrate a custom build tool in VS2010 that generates a .h-file from a source file. I've created a .xml, .targets and .props for the step. The XML is mostly copy-pasted from the MASM-file and ends with:

<ItemType Name="FOO" DisplayName="Foo compiler" />
<FileExtension Name="*.foo" ContentType="FOO" />
<ContentType Name="FOO" DisplayName="Foo compiler" ItemType="FOO" />

This maps all my .foo files to the Foo compiler that's defined in the .props:

<?xml version="1.0" encoding="utf-8"?>
<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <ItemGroup>
    <PropertyPageSchema Include="$(MSBuildThisFileDirectory)$(MSBuildThisFileName).xml" />
    <AvailableItemName Include="FOO">
      <Targets>FooCompile</Targets>
    </AvailableItemName>
  </ItemGroup>
  <UsingTask TaskName="FOO" TaskFactory="XamlTaskFactory" AssemblyName="Microsoft.Build.Tasks.v4.0">
    <Task>$(MSBuildThisFileDirectory)$(MSBuildThisFileName).xml</Task>
  </UsingTask>
  <Target Name="FooCompile" BeforeTargets="$(FOOBeforeTargets)" AfterTargets="$(FOOAfterTargets)" Condition="'@(FOO)' != ''" Outputs="%(FOO.Outputs)" Inputs="%(FOO.Identity);%(FOO.AdditionalDependencies);$(MSBuildProjectFile)" DependsOnTargets="_SelectedFiles">
    <Message Importance="High" Text="@(FOO)" />
    <FOO Condition="'@(FOO)' != '' and '%(FOO.ExcludedFromBuild)' != 'true'"
         CommandLineTemplate="%(FOO.CommandLineT开发者_Python百科emplate)"
         OutputFileName="%(FOO.OutputFileName)"
         Inputs="%(FOO.Identity)" />
  </Target>
</Project>

When I compile my project it successfully identifies and compiles my foo files:

1>FooCompile:
1>  apa.foo
1>FooCompile:
1>  banan.foo
1>ClCompile:
1>  test.cpp
1>  main.cpp

My question is why does it print "FooCompile:" once for each file while the ClCompile doesn't? Is there any way to change this?

If I change a cpp file and build, I'll also get this output once for each file, which I want to avoid:

1>FooCompile:
1>Skipping target "FooCompile" because all output files are up-to-date with respect to the input files.
1>FooCompile:
1>Skipping target "FooCompile" because all output files are up-to-date with respect to the input files.

---

The FooCompile target is using "target batching" which causes the target to iterate once for each item in the array specified for the Outputs attribute, %(Foo). The ClCompile target on the other hand operates using the entire item array @(ClCompile).

You can alter the verbosity of the logger to avoid the messages, specify /v:minimal, but of course you may be filtering out other information as well.