How to build Google RE2 using Cygwin?

Question

I'm getting these errors:

g++: unrecognized option '-pthread'
util/test.cc:1:0: warning: -fPIC ignored for target (all code is position independent)

(multiple), and finally:

/usr/lib/gcc/i686-pc-cygwin/4.5.3/../../../../i686-pc-cygwin/bin/ld: cannot find -lre2 collect2: ld returned 1 exit status

Any advice?

UPD full compiler log

g++ -o obj/so/test/charclass_test obj/so/re2/testing/charclass_test.o obj/so/util/pcre.o obj/so/util/random.o obj/so/util/thread.o obj/so/re2/testing/backtrack.o obj/so/re2/testing/dump.o obj/so/re2/testing/exhaustive_tester.o obj/so/re2/testing/null_walker.o obj/so/re2/testing/regexp_generator.o obj/so/re2/testing/string_generator.o obj/so/re2/testing/tester.o obj/so/util/test.o -Lobj/so -lre2 obj/libre2.a -pthread
g++: unrecognized option '-pthread'
/usr/lib/gcc/i686-pc-cygwin/4.5.3/../../../../i686-pc-cygwin/bin/ld: cannot find -lre2
collect2: ld returned 1 exit status
make: *** [obj/so/test/charclass_test] Error 1

Answer 1

I've done the following things to compile re2 library and tests on cygwin

1) Compilation and instalation of library

hg clone https://re2.googlecode.com/hg re2
cd re2
make
make install

2) Compilation of tests. Modify Makefile and replace this line:

$(CXX) -o $@ obj/so/re2/testing/$*.o $(STESTOFILES) obj/so/util/test.o -Lobj/so -lre2 obj/libre2.a $(LDFLAGS) $(LDPCRE)

with this line

$(CXX) -o $@ obj/so/re2/testing/$*.o $(STESTOFILES) obj/so/util/test.o -L/usr/local/lib -lre2 obj/libre2.a $(LDFLAGS) $(LDPCRE)

And after that do

make test

Library compiled for me without problem and with exception to one all tests passed.

You may also check this version of re2 for Visual Studio if you just need Windows version of library. http://code.google.com/p/re2win/

Answer 2

You can change the Makefile to pass the compilation. However, the test will still fail. I'd suggest you contact hg project owner to see why this does not work on cygwin.

$ hg diff
diff -r 9aa1d4f2954d Makefile
--- a/Makefile  Sun Oct 30 15:57:08 2011 +0000
+++ b/Makefile  Mon Dec 05 11:03:39 2011 -0800
@@ -191,7 +191,7 @@

 obj/so/test/%: obj/so/libre2.so obj/libre2.a obj/so/re2/testing/%.o $(STESTOFILES) obj/so/util/test.o
        @mkdir -p obj/so/test
-       $(CXX) -o $@ obj/so/re2/testing/$*.o $(STESTOFILES) obj/so/util/test.o -Lobj/so -lre2 obj/libre2.a $(LDFLAGS) $(LDPCRE)
+       $(CXX) -o $@ obj/so/re2/testing/$*.o $(STESTOFILES) obj/so/util/test.o -Lobj/so obj/libre2.a $(LDFLAGS) $(LDPCRE)

 obj/test/regexp_benchmark: obj/libre2.a obj/re2/testing/regexp_benchmark.o $(TESTOFILES) obj/util/benchmark.o
        @mkdir -p obj/test