use dummy backend for github ci

Author: ddiakopoulos

.github/workflows/cmake-multi-platform.yml

@@ -57,11 +57,13 @@ jobs:
     - name: Configure CMake
       # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
       # See https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html?highlight=cmake_build_type
+      # RTAUDIO_DUMMY=ON uses the dummy backend since CI runners have no audio hardware.
       run: >
         cmake -B ${{ steps.strings.outputs.build-output-dir }}
         -DCMAKE_CXX_COMPILER=${{ matrix.cpp_compiler }}
         -DCMAKE_C_COMPILER=${{ matrix.c_compiler }}
         -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
+        -DRTAUDIO_DUMMY=ON
         -S ${{ github.workspace }}
 
     - name: Build

CMakeLists.txt

@@ -27,8 +27,14 @@ target_include_directories(RunFilters PRIVATE
     example
 )
 
+# Option to use RtAudio dummy backend (for CI environments without audio hardware)
+option(RTAUDIO_DUMMY "Use RtAudio dummy backend (no audio output)" OFF)
+
 # Platform-specific RtAudio configuration for MoogLadderExample
-if(WIN32)
+if(RTAUDIO_DUMMY)
+    # Dummy backend - no platform API defined, RtAudio auto-selects dummy
+    message(STATUS "Using RtAudio dummy backend")
+elseif(WIN32)
     target_compile_definitions(MoogLadderExample PRIVATE __WINDOWS_DS__)
     target_link_libraries(MoogLadderExample PRIVATE dsound ole32 winmm)
 elseif(APPLE)