Discussion on: How To Make A Makefile

Nice intro article, thankyou.

I rewrote the core Solaris build system (6000+ Makefiles, lead a team of 4 for 3 years to deliver it), so my make knowledge is skewed towards the make which comes with Solaris Studio, but there are lots of similarities with the GNU version.

First comment: you define your c++ compiler as

CXX=clang++ -std=c++11
FLAGS=-Wall -Wextra -Werror -pedantic -c -g

I'd have written this differently:

CXX=clang++
CXXFLAGS= -std=c++11 -Wall -Wextra -Werror -pedantic -c -g

For C code, you'd use CC and CFLAGS, you'd also specify LDFLAGS for the linker, etc etc.

When it comes to your bin/boot target, I'd have written that differently too - to make the subdir dependency explicit:

bin:
    @mkdir -p bin

bin/boot: bin
    @(curlcmd....)
    @chmod 0555 $@

I did a lot of gnarly things with Solaris' make pattern matching rules
(for which I sometimes think I still need therapy). Case in point: Solaris has a closed subrepo for delivering binary blobs to partner companies. In order to remove a lot of extra work, I rewrote a few specific install rules to put those blobs in the right place in one hit:

INS.rename= $(INS.file) ; $(MV) $(@D)/$(<F) $@ ; \
    $(MV) $(@D:$(ROOT)/%=$(CLOSEDROOT)/%)/$(<F) \
    $(@D:$(ROOT)/%=$(CLOSEDROOT)/%)/$(@F)

Line noise making things faster, ftw.

The last comment I'll make is that the % character only matches the same pattern in the target and dependency - it's a rather simplistic regex

$(BUILDDIR)/%.o: $(SRCDIR)/%.c

We had to work around this all the time, and that limitation alone added several months to the project while we figured out the most efficient way of doing so.