循环依赖在 makefile 中下降

Question

I am having problems with my makefile It looks like this

name = project-name

testfiles = $(wildcard tst/*.cxx)
sourcefiles = $(wildcard src/*.cpp)
headerfiles = $(wildcard inc/*.hpp)

tests = $(testfiles:%=%.o)
sources = $(sourcefiles:%=%.o)
headers = $(headerfiles:%=%.gch)

location = /usr/local/include

flags = -Iinc -std=c++17 -pedantic -Wall

all: $(name)

%/:
    mkdir -p $@

clean:
    rm -f $(tests) $(sources) $(headers) $(name) test

install: $(name)
    install $^ $(location)/$<

run-%: %
    ./$<

test: $(tests)
    g++ -o $@ $^

$(name): $(sources)
    g++ -o $@ $^

pch: $(headers)

%.gch: %
    g++ -o $@ $< $(flags)

tst/catch.cxx.o: tst/catch.cxx inc/catchmain.hpp.gch
    g++ -o $@ -c $< $(flags)

tst/receive.cxx.o: tst/receive.cxx inc/catchtest.hpp.gch inc/server.hpp.gch
    g++ -o $@ -c $< $(flags)

src/server.cpp.o: src/server.cpp inc/server.hpp.gch inc/iostream.hpp.gch
    g++ -o $@ -c $< $(flags)

My folder structure is like this (image attached)

.
├── inc
│   ├── catchmain.hpp
│   ├── catchtest.hpp
│   ├── iostream.hpp
│   └── server.hpp
├── makefile
├── src
│   └── server.cpp
└── tst
    ├── catch.cxx
    └── receive.cxx

And when I run

make test

It shows that it dropped a circular dependency . I don't see what might cause that.

# The output of `make test`
make: Circular tst/catch.cxx <- tst/catch.cxx.o dependency dropped.
g++ -o inc/catchmain.hpp.gch inc/catchmain.hpp -Iinc -std=c++17 -pedantic -Wall
g++ -o tst/catch.cxx.o -c tst/catch.cxx -Iinc -std=c++17 -pedantic -Wall
make: Circular tst/receive.cxx <- tst/receive.cxx.o dependency dropped.
g++ -o inc/catchtest.hpp.gch inc/catchtest.hpp -Iinc -std=c++17 -pedantic -Wall
g++ -o inc/server.hpp.gch inc/server.hpp -Iinc -std=c++17 -pedantic -Wall
g++ -o tst/receive.cxx.o -c tst/receive.cxx -Iinc -std=c++17 -pedantic -Wall
g++ -o test tst/catch.cxx.o tst/receive.cxx.o

Answer 1

I just changed the extension from cxx to cpp and everything works without any errors. Weird

Answer 2

You had Circular dependency because

%: %.o

is a gnu make implicit rule