Profiling a CMake build

When CMake projects get big, configuring them might take quite a long time, especially if there is external content loaded or if there are lots of checks done for toolchain features. A first step to optimize this is to check what part of the configuration process takes up how much time. Since version 3.18, CMake includes command-line options to produce nice profiling graphs to investigate where the time is spent during configuration. By adding the --profiling-output and --profiling-format profiling flags, CMake will create profiling output. At the time of writing this book, only the Google trace format for the output format is supported. Despite this, the format and the file need to be specified to create the profiling information. A call to CMake to create a profiling graph could look like this:

cmake -S <sourceDir> -B <buildDir> --profiling-output 
./profiling.json --profiling-format=google-trace

This will write the profiling output to the...