Hi all,
With Ilia's help I could make some progress. I could come up with a Makefile
which demonstrates that the problem is definitely with the way I am writing the
Makefile:
<Makefile>
all: hello_protobuf
DEBUG = -g
LDFLAGS += `pkg-config --cflags --libs protobuf`
CXXFLAGS += `pkg-config --cflags --libs protobuf` -Wall $(DEBUG)
protoc_middleman: user.proto
protoc --cpp_out=. user.proto
@touch protoc_middleman
OBJS = hello_protobuf.o user.pb.o
hello_protobuf_1: hello_protobuf.cc protoc_middleman
pkg-config --cflags protobuf # fails if protobuf is not installed
$(CXX) hello_protobuf.cc user.pb.cc -o hello_protobuf `pkg-config --cflags
--libs protobuf`
hello_protobuf: protoc_middleman $(OBJS)
$(CXX) $(LDFLAGS) -o hello_protobuf $(OBJS)
.PHONY = clean
clean:
-rm -f *.o protoc_middleman
-rm -f hello_protobuf
</Makefile>
The target "hello_protobuf_1" builds fine. I basically copied it from the
Makefile in the examples directory:
$ make hello_protobuf_1
protoc --cpp_out=. user.proto
pkg-config --cflags protobuf # fails if protobuf is not installed
-pthread -I/usr/local/include
g++ hello_protobuf.cc user.pb.cc -o hello_protobuf `pkg-config --cflags --libs
protobuf`
$ ./hello_protobuf
Username: username and ID: 1
However, the more conventional looking target "hello_protobuf" fails to build.
I don't see any reason why it should fail:
$ make clean; make hello_protobuf
rm -f *.o protoc_middleman
rm -f hello_protobuf
protoc --cpp_out=. user.proto
g++ `pkg-config --cflags --libs protobuf` -Wall -g -c -o hello_protobuf.o
hello_protobuf.cc
g++ `pkg-config --cflags --libs protobuf` -Wall -g -c -o user.pb.o user.pb.cc
g++ `pkg-config --cflags --libs protobuf` -o hello_protobuf hello_protobuf.o
user.pb.o
hello_protobuf.o: In function `misc::User::set_username(char const*)':
user.pb.h:488: undefined reference to `google::protobuf::internal::kEmptyString'
...
Does anyone have any idea what I am missing with the target "hello_protobuf"?
From: [email protected]
To: [email protected]
CC: [email protected]
Subject: RE: [protobuf] Linker error
Date: Thu, 28 Feb 2013 11:10:24 -0800
Hi Ilia,
Though I have CFLAGS defined in my makefile I don't think that is being used.
The Makefile in the example directory (copied below) does not have either the
%.o:%.cc rule or any CFLAGS or CXXFLAGS but still it can build the executable
successfully using the default ones.
<ExampleMakefile>
# See README.txt.
.PHONY: all cpp java python clean
all: cpp java python
cpp: add_person_cpp list_people_cpp
java: add_person_java list_people_java
python: add_person_python list_people_python
clean:
rm -f add_person_cpp list_people_cpp add_person_java list_people_java
add_person_python list_people_python
rm -f javac_middleman AddPerson*.class ListPeople*.class
com/example/tutorial/*.class
rm -f protoc_middleman addressbook.pb.cc addressbook.pb.h
addressbook_pb2.py com/example/tutorial/AddressBookProtos.java
rm -f *.pyc
rmdir com/example/tutorial 2>/dev/null || true
rmdir com/example 2>/dev/null || true
rmdir com 2>/dev/null || true
protoc_middleman: addressbook.proto
protoc --cpp_out=. --java_out=. --python_out=. addressbook.proto
@touch protoc_middleman
add_person_cpp: add_person.cc protoc_middleman
pkg-config --cflags protobuf # fails if protobuf is not installed
c++ add_person.cc addressbook.pb.cc -o add_person_cpp `pkg-config --cflags
--libs protobuf`
list_people_cpp: list_people.cc protoc_middleman
pkg-config --cflags protobuf # fails if protobuf is not installed
c++ list_people.cc addressbook.pb.cc -o list_people_cpp `pkg-config
--cflags --libs protobuf`
javac_middleman: AddPerson.java ListPeople.java protoc_middleman
javac AddPerson.java ListPeople.java
com/example/tutorial/AddressBookProtos.java
@touch javac_middleman
add_person_java: javac_middleman
@echo "Writing shortcut script add_person_java..."
@echo '#! /bin/sh' > add_person_java
@echo 'java -classpath .:$$CLASSPATH AddPerson "$$@"' >> add_person_java
@chmod +x add_person_java
list_people_java: javac_middleman
@echo "Writing shortcut script list_people_java..."
@echo '#! /bin/sh' > list_people_java
@echo 'java -classpath .:$$CLASSPATH ListPeople "$$@"' >> list_people_java
@chmod +x list_people_java
add_person_python: add_person.py protoc_middleman
@echo "Writing shortcut script add_person_python..."
@echo '#! /bin/sh' > add_person_python
@echo './add_person.py "$$@"' >> add_person_python
@chmod +x add_person_python
list_people_python: list_people.py protoc_middleman
@echo "Writing shortcut script list_people_python..."
@echo '#! /bin/sh' > list_people_python
@echo './list_people.py "$$@"' >> list_people_python
@chmod +x list_people_python
</ExampleMakefile>
> Date: Thu, 28 Feb 2013 02:48:08 -0500
> Subject: Re: [protobuf] Linker error
> From: [email protected]
> To: [email protected]
> CC: [email protected]
>
> You don't appear to include the path to protobuf when compiling
> user.pb.o -- there's no explicit rule so it'll just $(CXXFLAGS). You
> should either add
>
> %.pb.o: %.pb.cc
> $(CC) $(CXXFLAGS) $(pkgconfig --cflags protobuf) -o $@ $^
>
> Or add CXXFLAGS = $(pkgconfig --cflags protobuf) at the top, which
> will make it add the include path everywhere. (I note you're using
> CFLAGS... afaik that doesn't get used by the default c++ compilation
> rule. Take a look at the commands make prints out and make sure
> they're what you'd expect.) Also you'll need this when compiling
> hello_protobuf.o, since it also needs the protobuf library.
>
> If the above doesn't explain the issue, you might paste the whole
> output from make which will include the actual commands being run.
>
> -ilia
>
> On Wed, Feb 27, 2013 at 4:01 PM, Mohammad Husain <[email protected]>
> wrote:
> > I am having a bizarre linker problem with the simple program I wrote with
> > protobuf. When I run the make command I see tons of linker errors like the
> > following:
> >
> > user.pb.o:(.rodata._ZTIN4misc4UserE[_ZTIN4misc4UserE]+0x10): undefined
> > reference to `typeinfo for google::protobuf::Message'
> > user.pb.o:(.rodata._ZTIN4misc13User_FullNameE[_ZTIN4misc13User_FullNameE]+0x0):
> > undefined reference to `vtable for __cxxabiv1::__si_class_type_info'
> > user.pb.o:(.rodata._ZTIN4misc13User_FullNameE[_ZTIN4misc13User_FullNameE]+0x10):
> > undefined reference to `typeinfo for google::protobuf::Message'
> > user.pb.o:(.eh_frame+0x38b): undefined reference to `__gxx_personality_v0'
> > collect2: error: ld returned 1 exit status
> > make: *** [hello_protobuf] Error 1
> >
> > However, the C++ example in the protobuf package builds and runs fine. Here
> > is the output of the pkgconfig command:
> >
> > $ pkg-config --cflags --libs protobuf
> > -pthread -I/usr/local/include -pthread -L/usr/local/lib -lprotobuf -lz
> > -lpthread
> > $ protoc --version
> > libprotoc 2.4.1
> > I am using version 2.4.1. I believe something is wrong with my Makefile. Can
> > anyone help?
> >
> > I tried to attach the source and Makefile but probably attachment is
> > disabled in the group. Here are my file contents:
> >
> > <user.proto>
> > package misc;
> >
> > message User {
> > required string username = 1;
> > required int32 id = 2;
> > optional string email = 3;
> >
> > message FullName {
> > required string firstName = 1;
> > optional string middleName = 2;
> > required string lastName = 3;
> > }
> >
> > optional FullName fullName = 4;;
> > }
> > </user.proto>
> >
> > <hello_protobuf.cpp>
> > #include <iostream>
> > #include "user.pb.h"
> >
> > int main(int argc, char **argv) {
> > misc::User u;
> >
> > u.set_username("username");
> > u.set_id(1);
> >
> > std::cout << "Username: " << u.username() << " and ID: " << u.id() <<
> > std::endl;
> >
> > return 0;
> > }
> > </hello_protobuf.cpp>
> >
> > <Makefile>
> > all: hello_protobuf
> >
> > CC = g++
> > DEBUG = -g
> > LIBS = `pkg-config --cflags --libs protobuf`
> > CFLAGS = -Wall $(DEBUG)
> > LFLAGS = -Wall $(DEBUG) $(LIBS)
> >
> > protoc_middleman: user.proto
> > protoc --cpp_out=. user.proto
> > @touch protoc_middleman
> >
> > OBJS = hello_protobuf.o user.pb.o
> >
> > hello_protobuf: $(OBJS) protoc_middleman
> > pkg-config --cflags protobuf # fails if protobuf is not installed
> > $(CC) $(LFLAGS) $(OBJS) -o hello_protobuf
> >
> > clean:
> > \rm *.o hello_protobuf
> > </Makefile>
> >
> > --
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> > "Protocol Buffers" group.
> > To unsubscribe from this group and stop receiving emails from it, send an
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> > To post to this group, send email to [email protected].
> > Visit this group at http://groups.google.com/group/protobuf?hl=en.
> > For more options, visit https://groups.google.com/groups/opt_out.
> >
> >
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