CODEWITHSUNDEEP
makefile
chew socks
chew socks

Reputation: 1446

Make target variable causes not input files

I am trying to use the following in a makefile, but when I type make filter_test it gives me the error below, and I can not figure out why. Note the spaces where the input files should be.

CXX=g++
CXXFLAGS=-O1 -pedantic -Wall -Werror -g
DEPS=p2.o recursive.o [email protected]

p2.o: p2.cpp ; $(CXXFLAGS) -c p2.cpp

recursive.o: recursive.cpp ; $(CXXFLAGS) -c recursive.cpp

filter_test:  p2.o [email protected] recursive.o ; $(CXX) $(CXXFLAGS) recursive.o p2.o [email protected]  -o aaa

Output:

g++ -O1 -pedantic -Wall -Werror -g         -o .cpp
g++: fatal error: no input files
compilation terminated.
make: *** [.cpp] Error 4

Upvotes: 0

Views: 166

Answers (1)

William Pursell
William Pursell

Reputation: 212178

$@ only has a value inside the recipe, so when make sees $@ in the prerequisite list, it treats it as an empty string. So make is trying to build the pre-requisite .cpp and using the default rule to build it. To fix this just write:

filter_test: p2.o filter_test.cpp recursive.o

Leave the recipe blank and let make use default rules.

Upvotes: 1

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