我想了解Makefile中的命令

Question

FC= ifort

FCFLAGS=-O2 -r8 -openmp -mcmodel=large -extend-source -shared-intel -I$(HOME)/usr/include

LDFLAGS=-L$(HOME)/usr/lib -lfftw3 -lm

TARGET=Project

Project: a.o b.o c.o d.o 

#
all : $(TARGET)

%: %.o

    $(FC) $(FCFLAGS) -o $@ $^ $(LDFLAGS)

%.o: %.f90

    $(FC) $(FCFLAGS) -c $<

all : $(TARGET)

clean :

    rm *.o

when I studied makefile, there is no information for

#
all : $(TARGET) 

and function of % and $^ . I wanna check about these things. Thanks for your help.

Answer 1

all is a target (repeated twice in that makefile for no reason). So is clean . Targets are how make works. See Rule Example .

$^ is one of the Automatic Variables available for use in target recipes.

% is a wildcard used in some make functions and in Pattern Rules .