3 ms·

What do you mean by "dependencies in the form of variables"?

by LukeShu 10y ago

wbl 10y ago
Let's say I need to build the library again with a different set of options. Make clean and rebuild is only solution, even if not needed.
- khedoros 10y ago
  You could also output to different directories, depending on the values of variables, like for separate debug and release builds. Of course, this is a work-around for variable dependencies. You'd have to change the filename somehow for every variable that you want to track.
- munificent 10y ago
  What I do is split the makefile in two. There's a top level makefile with targets like "make debug" and "make release". Those invoke a secondary makefile that actually builds things and takes options on the command line. That way I can build different configurations to different directories without having to copy/paste all of the rules for each configuration of each file. For example, the main makefile for Wren[1] has rules like: debug: @ $(MAKE) -f util/wren.mk MODE=debug That util/wren.mk [2] then uses "MODE" and a few other options, like: # Mode configuration. ifeq ($(MODE),debug) WREN := wrend C_OPTIONS += -O0 -DDEBUG -g BUILD_DIR := $(BUILD_DIR)/debug else WREN += wren C_OPTIONS += -O3 BUILD_DIR := $(BUILD_DIR)/release endif It has the real rules for compiling files: # VM object files. $(BUILD_DIR)/vm/%.o: src/vm/%.c $(VM_HEADERS) @ printf "%10s %-30s %s\n" $(CC) $< "$(C_OPTIONS)" @ mkdir -p $(BUILD_DIR)/vm @ $(CC) -c $(CFLAGS) -Isrc/include -Isrc/optional -Isrc/vm -o $@ $(FILE_FLAG) $< Took me a while to come up with this and quite some time to get it working, but I've been pretty happy with it so far. [1]: https://github.com/munificent/wren/blob/master/Makefile https://github.com/munificent/wren/blob/master/Makefile [2]: https://github.com/munificent/wren/blob/master/util/wren.mk https://github.com/munificent/wren/blob/master/util/wren.mk
- JdeBP 10y ago
  At this point in the chain of thinking, you should read http://cr.yp.to/redo/honest-script.html http://cr.yp.to/redo/honest-script.html
- LukeShu 10y ago
  How I handle that: .var.%: FORCE @printf '%s' '$(subst ','\'',$($*))' | sed 's|^|#|' | $(WRITE_IFCHANGED) $@ -include $(wildcard .var*) .PHONY: FORCE Where WRITE_IFCHANGED is a program that essentially does 'cat > $1', but only if doing so would create or change the file. https://lukeshu.com/git/autothing/tree/build-aux/write-ifchanged?h=mod-write-ifchanged https://lukeshu.com/git/autothing/tree/build-aux/write-ifcha... Then, if a file depends on the value of a variable, I have it depend on .var.VARNAME. Of course, that means you may have to do something like $(filter-out .var.%,$^) in the command to generate a file.

What do you mean by "dependencies in the form of variables"?

by LukeShu 10y ago

What do you mean by "dependencies in the form of variables"?

wbl 10y ago

Let's say I need to build the library again with a different set of options. Make clean and rebuild is only solution, even if not needed.

khedoros 10y ago
You could also output to different directories, depending on the values of variables, like for separate debug and release builds. Of course, this is a work-around for variable dependencies. You'd have to change the filename somehow for every variable that you want to track.
munificent 10y ago
What I do is split the makefile in two. There's a top level makefile with targets like "make debug" and "make release". Those invoke a secondary makefile that actually builds things and takes options on the command line. That way I can build different configurations to different directories without having to copy/paste all of the rules for each configuration of each file. For example, the main makefile for Wren[1] has rules like: debug: @ $(MAKE) -f util/wren.mk MODE=debug That util/wren.mk [2] then uses "MODE" and a few other options, like: # Mode configuration. ifeq ($(MODE),debug) WREN := wrend C_OPTIONS += -O0 -DDEBUG -g BUILD_DIR := $(BUILD_DIR)/debug else WREN += wren C_OPTIONS += -O3 BUILD_DIR := $(BUILD_DIR)/release endif It has the real rules for compiling files: # VM object files. $(BUILD_DIR)/vm/%.o: src/vm/%.c $(VM_HEADERS) @ printf "%10s %-30s %s\n" $(CC) $< "$(C_OPTIONS)" @ mkdir -p $(BUILD_DIR)/vm @ $(CC) -c $(CFLAGS) -Isrc/include -Isrc/optional -Isrc/vm -o $@ $(FILE_FLAG) $< Took me a while to come up with this and quite some time to get it working, but I've been pretty happy with it so far. [1]: https://github.com/munificent/wren/blob/master/Makefile https://github.com/munificent/wren/blob/master/Makefile [2]: https://github.com/munificent/wren/blob/master/util/wren.mk https://github.com/munificent/wren/blob/master/util/wren.mk
JdeBP 10y ago
At this point in the chain of thinking, you should read http://cr.yp.to/redo/honest-script.html http://cr.yp.to/redo/honest-script.html
LukeShu 10y ago
How I handle that: .var.%: FORCE @printf '%s' '$(subst ','\'',$($*))' | sed 's|^|#|' | $(WRITE_IFCHANGED) $@ -include $(wildcard .var*) .PHONY: FORCE Where WRITE_IFCHANGED is a program that essentially does 'cat > $1', but only if doing so would create or change the file. https://lukeshu.com/git/autothing/tree/build-aux/write-ifchanged?h=mod-write-ifchanged https://lukeshu.com/git/autothing/tree/build-aux/write-ifcha... Then, if a file depends on the value of a variable, I have it depend on .var.VARNAME. Of course, that means you may have to do something like $(filter-out .var.%,$^) in the command to generate a file.