Compiling XIBs with CMake without Xcode

I’ve been enjoying using the JetBrains IDE CLion to do some refactoring and improvements to the Auctions code base. However, when I tried to build the Mac app bundle with it, the app failed to launch:

2022-07-30 19:54:15.117 Auctions[80371:16543044] Unable to load nib file: Auctions, exiting

The XIB files were definitely part of the CMake project. I later learned that CMake does not automatically add XIB compilation targets to a project. It relies on the Xcode generator to do that.

I found a long-archived documentation page from CMake on the Kitware GitLab that described a method to build NIB files from XIBs, and have modified it to make it simpler for Auctions.

You can see the change in the commit diff, but I’ll include the snippet here for posterity.

First, you define an array with the XIB file names with no suffix. For instance, I’ve done set(COCOA_UI_XIBS AXAccountsWindow AXSignInWindow Auctions) for the three XIB files presently in the codebase.

Then we have the loop to build them:

find_program(IBTOOL ibtool REQUIRED)
foreach(XIBFILE ${COCOA_UI_XIBS})
    add_custom_command(TARGET Auctions POST_BUILD
            COMMAND ${IBTOOL} --compile ${CMAKE_CURRENT_BINARY_DIR}/Auctions.app/Contents/Resources/${XIBFILE}.nib ${CMAKE_CURRENT_SOURCE_DIR}/${XIBFILE}.xib
            COMMENT "Compiling NIB file ${XIBFILE}.nib")
endforeach()

Now it starts correctly and works properly when built from within CLion. This was surprisingly difficult to debug and fix, so I hope this post can help others avoid the hours of dead ends that I endured.

Until next time, Happy Hacking!