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diff --git a/www/text.causal.agency/001-make.7 b/www/text.causal.agency/001-make.7 new file mode 100644 index 00000000..b4805729 --- /dev/null +++ b/www/text.causal.agency/001-make.7 @@ -0,0 +1,159 @@ +.Dd September 17, 2018 +.Dt MAKE 7 +.Os "Causal Agency" +. +.Sh NAME +.Nm Using Make +.Nd writing less Makefile +. +.Sh DESCRIPTION +Let's talk about +.Xr make 1 . +I think an important thing to know about +.Xr make 1 +is that you don't need to write a +.Pa Makefile +to use it. +There are default rules +for C, C++ and probably Fortran. +To build +.Pa foo +from +.Pa foo.c , +just run: +. +.Pp +.Dl make foo +. +.Pp +The default rule for C files uses the +.Ev CFLAGS +variable, +so you can set that in the environment +to pass flags to the C compiler: +. +.Pp +.Dl CFLAGS=-Wall make foo +. +.Pp +It also uses +.Ev LDLIBS +for linking, +so you can add libraries with: +. +.Pp +.Dl LDLIBS=-lcurses make foo +. +.Pp +Obviously writing this every time +would become tedious, +so it might be time to write a +.Pa Makefile . +But it really doesn't need much: +. +.Bd -literal -offset indent +CFLAGS += -Wall -Wextra +LDLIBS = -lcurses + +foo: +.Ed +. +.Pp +Assigning +.Ev CFLAGS +with +.Ql += +preserves the system default +or anything passed in the environment. +Declaring +.Pa foo +as the first rule +makes it the default when +.Ql make +is run without a target. +Note that the rule doesn't need a definition; +the default will still be used. +. +.Pp +If +.Pa foo +is built from serveral source files, +unfortunately a rule definition is required: +. +.Bd -literal -offset indent +OBJS = foo.o bar.o baz.o + +foo: $(OBJS) + $(CC) $(LDFLAGS) $(OBJS) $(LDLIBS) -o $@ +.Ed +. +.Pp +This rule uses +.Ev LDFLAGS +for passing linker flags, +which is what the default rule does. +The +.Ql $@ +variable here expands to +.Ql foo , +so this rule can be copied easily +for other binary targets. +. +.Pp +If some sources depend on a header file, +they can be automatically rebuilt +when the header changes +by declaring a dependency rule: +. +.Pp +.Dl foo.o bar.o: foo.h +. +.Pp +Note that several files can appear +either side of the +.Ql ":" . +. +.Pp +Lastly, +it's always nice to add a +.Cm clean +target: +. +.Bd -literal -offset indent +clean: + rm -f $(OBJS) foo +.Ed +. +.Pp +I hope this helps getting started with +.Xr make 1 +without writing too much +.Pa Makefile ! +. +.Sh EXAMPLES +The example +.Pa Makefile +in its entirety: +. +.Bd -literal -offset indent +CFLAGS += -Wall -Wextra +LDLIBS = -lcurses +OBJS = foo.o bar.o baz.o + +foo: $(OBJS) + $(CC) $(LDFLAGS) $(OBJS) $(LDLIBS) -o $@ + +foo.o bar.o: foo.h + +clean: + rm -f $(OBJS) foo +.Ed +. +.Sh AUTHORS +.An Mt june@causal.agency +. +.Pp +This document is produced from +.Xr mdoc 7 +source available from +.Lk https://git.causal.agency/src/tree/www/text.causal.agency |