# Unknown CMake command "juce\_add\_gui\_app" **URL:** \ **Category:** General JUCE discussion\ **Created:** [October 12, 2020, 8:33am UTC](https://forum.juce.com/t/unknown-cmake-command-juce-add-gui-app/42175 "2020-10-12T08:33:09Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![aquariusgirl](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@aquariusgirl](https://forum.juce.com/u/aquariusgirl)\ **Post date:** [October 12, 2020, 8:33am UTC](https://forum.juce.com/t/unknown-cmake-command-juce-add-gui-app/42175/1 "2020-10-12T08:33:09Z")
Well, I have progressed now with the official CMake project of JUCE. I cloned this whole directory: [https://github.com/juce-framework/JUCE](https://github.com/juce-framework/JUCE) I went inside: ``` .../temp/JUCE/examples/CMake/GuiApp$ ls build CMakeLists.txt MainComponent.cpp MainComponent.h Main.cpp ``` I made that `build` directory for executing `cmake`. Executing the cmake is resulting in following error: ``` .../temp/JUCE/examples/CMake/GuiApp/build$ cmake .. -- The C compiler identification is GNU 7.5.0 -- The CXX compiler identification is GNU 7.5.0 -- Check for working C compiler: /usr/bin/cc -- Check for working C compiler: /usr/bin/cc -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Detecting C compile features -- Detecting C compile features - done -- Check for working CXX compiler: /usr/bin/c++ -- Check for working CXX compiler: /usr/bin/c++ -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Detecting CXX compile features -- Detecting CXX compile features - done CMake Error at CMakeLists.txt:39 (juce_add_gui_app): Unknown CMake command "juce_add_gui_app". -- Configuring incomplete, errors occurred! See also "/home/xyz/Documents/abc/work/juce/temp/JUCE/examples/CMake/GuiApp/build/CMakeFiles/CMakeOutput.log". ``` Was I supposed to change something in the CMakeList.txt? Please guide about how to get rid of `Unknown CMake command "juce_add_gui_app".` . ---
**Author:** ![reuk](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/reuk/32/21494_2.png) [@reuk](https://forum.juce.com/u/reuk)\ **Post date:** [October 12, 2020, 9:12am UTC](https://forum.juce.com/t/unknown-cmake-command-juce-add-gui-app/42175/2 "2020-10-12T09:12:23Z")
There are instructions for building the GuiApp example in `examples/CMake/GuiApp/CMakeLists.txt`. If you’re building the GuiApp example from inside JUCE (as you’ve attempted here), you’ll need to run cmake from the top level of the repo, like so: ```auto cmake . -B cmake-build-dir -D JUCE_BUILD_EXAMPLES=ON cmake --build cmake-build-dir --target GuiApp ``` However, if you’re starting a new JUCE project, it’s recommended to copy the whole GuiApp folder to a new location outside the repo, and then to use `add_subdirectory(path/to/JUCE)` to point the project to a copy of JUCE. ---
**Author:** ![aquariusgirl](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@aquariusgirl](https://forum.juce.com/u/aquariusgirl)\ **Post date:** [October 12, 2020, 10:35am UTC](https://forum.juce.com/t/unknown-cmake-command-juce-add-gui-app/42175/3 "2020-10-12T10:35:51Z")
Am thankful for your patience. I am not well versed with CMake yet. I ran `cmake . -B cmake-build-dir -D JUCE_BUILD_EXAMPLES=ON` in the top level directory of the repository. It complained about missing ‘webkit2gtk-4.0’ , ‘gtk±x11-3.0’, and ‘alsa’. Is it important to have these dependencies? Are they optional? Secondly, where am I supposed to run the second command? `cmake --build cmake-build-dir --target GuiApp`? I ran it in the top level repo’ build dir like this: `cmake .. --build cmake-build-dir --target ../examples/CMake/GuiApp` It said: `CMake Error: The source "/home/xyz/Documents/abc/work/juce/temp/JUCE/examples/CMake/GuiApp/CMakeLists.txt" does not match the source "/home/xyz/Documents/abc/work/juce/temp/JUCE/CMakeLists.txt" used to generate cache. Re-run cmake with a different source directory.` Running it in the `JUCE/examples/CMake/` repo complains about `Unknown CMake command "juce_add_gui_app"`. Where am I supposed to run the second command? ---
**Author:** ![aquariusgirl](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@aquariusgirl](https://forum.juce.com/u/aquariusgirl)\ **Post date:** [October 12, 2020, 10:43am UTC](https://forum.juce.com/t/unknown-cmake-command-juce-add-gui-app/42175/4 "2020-10-12T10:43:20Z")
Besides what I wrote in the above post, I have also enabled `find_package(JUCE CONFIG REQUIRED)` in th GuiApp’s CMakeList.txt. Now the innermost cmake says: ``` CMake Error at CMakeLists.txt:25 (find_package): Could not find a package configuration file provided by "JUCE" with any of the following names: JUCEConfig.cmake juce-config.cmake Add the installation prefix of "JUCE" to CMAKE_PREFIX_PATH or set "JUCE_DIR" to a directory containing one of the above files. If "JUCE" provides a separate development package or SDK, be sure it has been installed. ``` should I have done this? I have added `list(APPEND CMAKE_PREFIX_PATH "/home/xyz/Documents/abc/work/juce/temp/JUCE/")` That doesn’t seem to help though. ---
**Author:** ![aquariusgirl](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@aquariusgirl](https://forum.juce.com/u/aquariusgirl)\ **Post date:** [October 12, 2020, 12:19pm UTC](https://forum.juce.com/t/unknown-cmake-command-juce-add-gui-app/42175/5 "2020-10-12T12:19:07Z")
Again a change: I cleaned the build folders and started again: This time I first uncommented `find_package(JUCE)` in `/GuiApp'` CMakeList.txt. Then I ran `cmake .. . -B cmake-build-dir -D JUCE_BUILD_EXAMPLES=ON` on the top level directory. It says: ``` -- Checking for modules 'webkit2gtk-4.0;gtk+-x11-3.0' -- No package 'webkit2gtk-4.0' found -- No package 'gtk+-x11-3.0' found -- Checking for module 'alsa' -- No package 'alsa' found -- Configuring juceaide -- Building juceaide -- Exporting juceaide CMake Error at examples/CMake/GuiApp/CMakeLists.txt:27 (find_package): Could not find a package configuration file provided by "JUCE" with any of the following names: JUCEConfig.cmake juce-config.cmake Add the installation prefix of "JUCE" to CMAKE_PREFIX_PATH or set "JUCE_DIR" to a directory containing one of the above files. If "JUCE" provides a separate development package or SDK, be sure it has been installed. -- Configuring incomplete, errors occurred! ``` I tried to find where is JUCEConfig.cmake ``` /work/juce/temp/JUCE/build$ find . -name JUCEConfig.cmake ./cmake-build-dir/tools/JUCEConfig.cmake ``` I am supposed to put this path in CMAKE\_PREFIX\_PATHS? ---
**Author:** ![reuk](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.juce.com/reuk/32/21494_2.png) [@reuk](https://forum.juce.com/u/reuk)\ **Post date:** [October 12, 2020, 12:28pm UTC](https://forum.juce.com/t/unknown-cmake-command-juce-add-gui-app/42175/6 "2020-10-12T12:28:22Z")
To resolve the missing packages, you should install `libwebkit2gtk-4.0-dev` and `libasound2-dev`: ```auto sudo apt install libwebkit2gtk-4.0-dev libasound2-dev ``` To build a new GUI App project with JUCE/CMake, do this (starting from scratch): - Copy the GuiApp folder to a new location. - In the GuiApp CMakeLists that you copied, replace the `add_subdirectory(JUCE)` line with `add_subdirectory("/home/xyz/Documents/abc/work/juce/temp/JUCE" JUCE)`, replacing the path with the real location of the JUCE repo on your system. - From the GuiApp folder that you copied, run - `cmake . -B cmake-build-dir` - This will create a build tree folder named `cmake-build-dir` - `cmake --build cmake-build-dir` - This will build all targets in the `cmake-build-dir` folder. ---
**Author:** ![aquariusgirl](https://avatars.discourse-cdn.com/v4/letter/a/779978/32.png) [@aquariusgirl](https://forum.juce.com/u/aquariusgirl)\ **Post date:** [October 12, 2020, 1:58pm UTC](https://forum.juce.com/t/unknown-cmake-command-juce-add-gui-app/42175/7 "2020-10-12T13:58:10Z")
I am utterly thankful for the patience that you have shown here. I followed all your steps and this time there were no errors. I found the executable in the build directory and I ran it successfully. Now I hope to speed up towards writing/learning coding.