Question

So I have a variable:

PROGS = element0 \
        element1

I have variables for each one:

element0_SRCS = src/xxx.c src/q.c
element1_SRCS = src/xxx.c src/z.c

If I have another set of variables then I can do what I want rather easily:

element0_OBJS = src/xxx.o src/q.o
element1_OBJS = src/xxx.o src/z.o

ALL_PROGS = $(foreach p, $(PROGS), $(p)_prog)
all : $(ALL_PROGS)

.SECONDEXPANSION:
%_prog : $$($$*_OBJS)
     gcc - blah blah

However, I want to eliminate the need of the “_OBJS” vars and use the _SRCS ones. I can do this individual with each prog:

element0_prog : $(element0_SRCS:.c=.o)

Various attempts to use second expansion to recreate the %_prog rule though have failed.

$$($$*_SRCS:.c=.o) ==> target pattern contains no ‘%’

$$(patsubst %.c,%.o,$$($$*_SRCS)) ==> builds the target with .c files instead of .o files.

Pretty much at a loss here.

Answer 1

Use static pattern rule:

prog_objs = $($*_SRCS:.c=.o)

.SECONDEXPANSION:
$(ALL_PROGS) : %_prog : $$(prog_objs)
    gcc - blah blah