Qt 4.7 and VS2010 Moc problem

When the projects grow bigger, the project settings might go out of control sometimes. Today I want to share a quick fix for one specific such case.

My case and fix happens under Qt version 4.7, Visual Studio 2010 and Qt Visual Studio add-on 1.1.7; however it might be applicable to other versions too.

When you have an error like "moc: Too many input files specified":

moc: Too many input files specified
1>  Usage: moc [options] <header-file>
1>    -o<file>           write output to file rather than stdout
1>    -I<dir>            add dir to the include path for header files
1>    -E                 preprocess only; do not generate meta object code
1>    -D<macro>[=<def>]  define macro, with optional definition
1>    -U<macro>          undefine macro
1>    -i                 do not generate an #include statement
1>    -p<path>           path prefix for included file
1>    -f[<file>]         force #include, optional file name
1>    -nn                do not display notes
1>    -nw                do not display warnings
1>    @<file>            read additional options from file
1>    -v                 display version of moc

One of the general cases I have encountered is the problem caused by the spaces in the project path. A quick solution might be getting rid of that ambiguity by changing the workspace and/or paths of environment variables.

However, in my case, I have multiple moc files and I get this error for only a few files. In that case, open the project settings file with a text editor (i.e. "vi <project_name>.vcxproj"), and look for "moc_". You will see that some moc files might be excluded from the build.

Normal:

<ClCompile Include="GeneratedFiles\Release\moc_normal_file.cpp" />

Excluded:

<ClCompile Include="GeneratedFiles\Release\moc_excluded_file.cpp" /> <ClComp      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">true</ExcludedFromBuild>      <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">true</ExcludedFromBuild>   <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">true</ExcludedFromBuild>    </ClCompile>

Changing the excluded file to a normal form would make it be compiled and linked as the usual files:

<ClCompile Include="GeneratedFiles\Release\moc_excluded_file.cpp" />

If not, I would advise to look for more changed/corrupted settings in that file, especially with the filename associated with the error above.