Generate ctags file for C or C++ files and its depedencies (included header files). This could avoid you to always generate a huge tags file.

ctags_with_dep.sh

#!/bin/sh

# https://www.topbug.net/blog/2012/03/17/generate-ctags-files-for-c-slash-c-plus-plus-source-files-and-all-of-their-included-header-files/
# ./ctags_with_dep.sh file1.c file2.c ... to generate a tags file for these files.

gcc -M "$@" | sed -e 's/[\\ ]/\n/g' | \
        sed -e '/^$/d' -e '/\.o:[ \t]*$/d' | \
        ctags -L - --c++-kinds=+p --fields=+iaS --extra=+q

I like it.
Add this directly into my makefile.

	@$(CC) -M $(CFLAGS) $(SRC) | sed -e 's/[\\ ]/\n/g' | \
		sed -e '/^$$/d' -e '/\.o:[ \t]*$$/d' | \
		ctags -L - --c-kinds=+p --fields=+iaSl --extra=+q --langmap=c:.c.h

This won't work on MacOS since sed on MacOS does not interpret '\n' as a newline. So, another way of doing this would be:

gcc -M $* | tr '\\ ' '\n' | sed -e '/^$/d' -e '/\.o:[ \t]*$/d' | \
        ctags -L - --c++-kinds=+p --fields=+iaS --extra=+q

you could also replace the sed with gsed, and another hacks. but the above works for me. Thanks for the idea!

Well, it works just fine for me as of February 2023 on an Intel Mac.