Test your make-fu (update Makefile to maintain a version.h file)

[Dirk Hohndel]

Oh Makefile gurus (I'm looking at you, Linus, Carl, Cristian...)

Could someone turn this into a patch for our Makefile that just DWIM?

I played with a few ways to do this and I just cannot get it to do what
I mean. It either breaks recompilation of Subsurface, or ignores new
values for git describe :-(

/D 

"Lubomir I. Ivanov" <neolit123 at gmail.com> writes:

> your make-fu is probably better than my, but here is an attempt to
> write a Makefile that reads a version.h file and compares that to a
> "git describe" version.
> there are some comments in the code.
>
> ideas partially from the other thread on this topic.
>
> ----------------------------------------
> Makefile:
> ----------------------------------------
> # version rule goes here
> all: version test.o
>
> define update_ver
> 	@echo updating version.h to $(1)
> 	$(shell echo \#define VERSION \"$(1)\" > version.h)
> endef
>
> version:
> # if not i na git repo VER should be ""
> 	$(eval VER = $(shell git describe --tags --abbrev=7 2>&1 | \
> 		grep -E -v "Not a git repository|No names found"))
> # check contents of version.h for $(VER)
> 	$(eval VER_MATCH = $(findstring "$(VER)", $(shell cat version.h | cut
> -d' ' -f3)))
> # ugly flip of the value here, since i need the inverse and i don't
> know about a $(ifnot...) function
> 	$(if $(VER_MATCH), $(eval VER_MATCH =), $(eval VER_MATCH = NOUPDATE))
> # if there is a version from git and it does not match the one in the
> version.h let's update version.h
> 	$(if $(VER), $(if $(VER_MATCH), $(call update_ver,$(VER))))
>
> # file depends on version.h
> test.o: test.c version.h
> 	gcc test.c -o test.o
>
> clean:
> 	rm test.o
>
> ----------------------------------------
> version.h
> ----------------------------------------
> #define VERSION "v1.0.0"
>
>
> ------------------
> other notes:
> - uses only grep, cat, cut
> - this is a portable version, things like "if / fi" aren't portable
> outside of bash/sh, but the current Makefile uses them anyway.
> - runs on the windows native shell and on bash/sh with the msys toolchain.
> - seems to work with GNU Make 3.82
>
> lubomir
> --