Disable make builtin rules and variables from insi

Question

I want to disable builtin rules and variables as per passing the -r and -R options to GNU make, from inside the make file. Other solutions that allow me to do this implicitly and transparently are also welcome.

I've found several references to using MAKEFLAGS, and had similar problems.

Answer 1

This works for me:

# Disable implicit rules to speedup build
.SUFFIXES:
SUFFIXES :=
%.out:
%.a:
%.ln:
%.o:
%: %.o
%.c:
%: %.c
%.ln: %.c
%.o: %.c
%.cc:
%: %.cc
%.o: %.cc
%.C:
%: %.C
%.o: %.C
%.cpp:
%: %.cpp
%.o: %.cpp
%.p:
%: %.p
%.o: %.p
%.f:
%: %.f
%.o: %.f
%.F:
%: %.F
%.o: %.F
%.f: %.F
%.r:
%: %.r
%.o: %.r
%.f: %.r
%.y:
%.ln: %.y
%.c: %.y
%.l:
%.ln: %.l
%.c: %.l
%.r: %.l
%.s:
%: %.s
%.o: %.s
%.S:
%: %.S
%.o: %.S
%.s: %.S
%.mod:
%: %.mod
%.o: %.mod
%.sym:
%.def:
%.sym: %.def
%.h:
%.info:
%.dvi:
%.tex:
%.dvi: %.tex
%.texinfo:
%.info: %.texinfo
%.dvi: %.texinfo
%.texi:
%.info: %.texi
%.dvi: %.texi
%.txinfo:
%.info: %.txinfo
%.dvi: %.txinfo
%.w:
%.c: %.w
%.tex: %.w
%.ch:
%.web:
%.p: %.web
%.tex: %.web
%.sh:
%: %.sh
%.elc:
%.el:
(%): %
%.out: %
%.c: %.w %.ch
%.tex: %.w %.ch
%: %,v
%: RCS/%,v
%: RCS/%
%: s.%
%: SCCS/s.%
.web.p:
.l.r:
.dvi:
.F.o:
.l:
.y.ln:
.o:
.y:
.def.sym:
.p.o:
.p:
.txinfo.dvi:
.a:
.l.ln:
.w.c:
.texi.dvi:
.sh:
.cc:
.cc.o:
.def:
.c.o:
.r.o:
.r:
.info:
.elc:
.l.c:
.out:
.C:
.r.f:
.S:
.texinfo.info:
.c:
.w.tex:
.c.ln:
.s.o:
.s:
.texinfo.dvi:
.el:
.texinfo:
.y.c:
.web.tex:
.texi.info:
.DEFAULT:
.h:
.tex.dvi:
.cpp.o:
.cpp:
.C.o:
.ln:
.texi:
.txinfo:
.tex:
.txinfo.info:
.ch:
.S.s:
.mod:
.mod.o:
.F.f:
.w:
.S.o:
.F:
.web:
.sym:
.f:
.f.o:

Put this in a file named disable_implicit_rules.mk and include it in every makefile.

Answer 2

https://www.gnu.org/software/make/manual/make.html#Canceling-Rules

# Disable built-in rules and variables
MAKEFLAGS += --no-builtin-rules
MAKEFLAGS += --no-builtin-variables

# Makefile begins
main: main.c
    cc main.c -o main

Answer 3

@hseldon has the right idea because .SUFFIXES doesn't cover the match-everything built-in implicit rules. However, I don't think his syntax is exactly right.

MAKEFLAGS += --no-builtin-rules

.SUFFIXES:
.SUFFIXES: .you .own .here

See http://www.gnu.org/software/make/manual/make.html#Match_002dAnything-Rules and http://www.gnu.org/software/make/manual/make.html#index-g_t_002eSUFFIXES-998

Answer 4

You could start the Makefile with a #! and call it something different so people don't try to use make directly:

#!/usr/bin/make -rRf
# ...

This will cause horrific problems if GNU make is not the system make. Maybe a wrapper script?

You can also read $(MAKEFLAGS) and make sure the required flags are present.

Answer 5

################################################################
# DISABLE BUILT-IN RULES
#
.SUFFIXES:
    MAKEFLAGS += -r

Answer 6

Disabling the built-in rules is done by writing an empty rule for .SUFFIXES:

.SUFFIXES:

Having erased the built-in rules, I'm not sure that erasing the built-in variables helps you much more than just remembering to set them yourself or not use them, but you could use something like

$(foreach V
    $(shell make -p -f/dev/null 2>/dev/null | sed -n '/^[^:#= ]* *=/s/ .*//p'),
    $(if $(findstring default,$(origin $V)),$(eval $V=)))

...which is admittedly fairly crazy. If there is a way to get a list of the defined variables from within make (instead of shelling out to another make), it would be viable. As it is, it's not really much better than

CC=
CXX=
# etc, for each likely built-in variable