Question

I have a Makefile that I use to build executable on mac os x, using mpicc compiler, linking mkl_lapack.h library.
Now this Makefile is perfectly working, the only problem is that I don’t know what to add if I want to compile Eigenvalues.c linking other .c files, if I want to link myfile.c where do I have to write it in Makefile?

MKL_INCLUDE=/opt/intel/mkl/include
MKLROOT=/opt/intel/mkl/lib

CC = mpicc
LD = mpicc
IFLAGS = -I$(MKL_INCLUDE)
CFLAGS = -Wall -O2 $(IFLAGS) -std=c99

LFLAGS =  $(MKLROOT)/libmkl_intel_lp64.a $(MKLROOT)/libmkl_sequential.a    $(MKLROOT)/libmkl_core.a  -lpthread -lm 

PROGRAMS = Eigenvalues

all: $(PROGRAMS)

Eigenvalues: 
    $(CC) $(CFLAGS) -o $@ $^ $(LFLAGS) 

%.o: %.c
    @echo C compiling $@
    $(CC) -c $(CFLAGS) -o $@ $<

clean:
    rm -rf *.o $(PROGRAMS)

Eigenvalues: Eigenvalues.c

Answer 1

Simply have the Eigenvalues target depend on all the .o files (not the .c files, as you have!) that make up the application. Conventionally, the list of these objects is put in a variable:

PROGRAMS = Eigenvalues
Eigenvalues_OBJS = Eigenvalues.o foo.o bar.o #etc

all: $(PROGRAMS)

Eigenvalues: $(Eigenvalues_OBJS)
        $(CC) $(CFLAGS) -o $@ $^ $(LFLAGS) 

# delete the "Eigenvalues: Eigenvalues.c" line,
# leave everything else as you have it

By the way, since you are using the standard variable names $(CC) and $(CFLAGS), you can leave out the %.o: %.c rule entirely; Make has a built-in rule that does the same thing.