title: Reference header from other project in Omnet++
body: <p>I am currently trying to build a shared library with C++ code which I can use in multiple Omnet++ projects. I am using Omnet++ 5.3. I created a new Omnet++ project for this purpose, put in my source files and selected the following options in the makemake options:</p>
  
  <p>Target type: <code>Shared library</code> and <code>Export this shared/static library for other projects</code></p>
  
  <p>Compile: <code>Export include paths for other projects</code> and <code>Force compiling object files for use in DLLs</code></p>
  
  <p>In the referencing project I did the following in the makemake options:</p>
  
  <p>Target: <code>Executable</code></p>
  
  <p>Compile: <code>Add include paths exported from referenced projects</code> and <code>Add include dirs and other compile options from enabled project features</code></p>
  
  <p>Link: <code>Link with libraries exported from referenced projects</code> and <code>Add libraries and other linker options from enabled project features</code></p>
  
  <p>Additionally, I added the shared library project to the project references. In the referencing project I want to include a header file of the shared library project. However, I cannot include it. I tried different schemes for including it such as <code>"MODULENAME/HEADERFILE"</code>, <code>&lt;MODULENAME/HEADERFILE&gt;</code>, <code>"HEADERFILE"</code>, <code>&lt;HEADERFILE&gt;</code>. I tried it on macOS and on Windows. Any ideas how to fix this? Has this something to do with the changed include scheme in the newer Omnet versions where the relative path to header files has to be provided? Thanks a lot!</p>