I am trying to compile flatbuffers with cygwin.
Here is what I do:
git clone https://github.com/google/flatbuffers.git && cd ./flatbuffers
Than:
cmake .
-- The C compiler identification is GNU 10.2.0
-- The CXX compiler identification is GNU 10.2.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc - works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++.exe
-- Check for working CXX compiler: /usr/bin/c++.exe - works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Looking for strtof_l
-- Looking for strtof_l - not found
-- Looking for strtoull_l
-- Looking for strtoull_l - not found
-- `tests/monster_test.fbs`: add generation of C++ code with '--no-includes;--gen-compare'
-- `tests/monster_test.fbs`: add generation of binary (.bfbs) schema
-- `tests/namespace_test/namespace_test1.fbs`: add generation of C++ code with '--no-includes;--gen-compare'
-- `tests/namespace_test/namespace_test2.fbs`: add generation of C++ code with '--no-includes;--gen-compare'
-- `tests/union_vector/union_vector.fbs`: add generation of C++ code with '--no-includes;--gen-compare'
-- `tests/optional_scalars.fbs`: add generation of C++ code with '--no-includes;--gen-compare'
-- `tests/native_type_test.fbs`: add generation of C++ code with ''
-- `tests/arrays_test.fbs`: add generation of C++ code with '--scoped-enums;--gen-compare'
-- `tests/arrays_test.fbs`: add generation of binary (.bfbs) schema
-- `tests/monster_test.fbs`: add generation of C++ embedded binary schema code with '--no-includes;--gen-compare'
-- `tests/monster_extra.fbs`: add generation of C++ code with '--no-includes;--gen-compare'
-- `samples/monster.fbs`: add generation of C++ code with '--no-includes;--gen-compare'
-- `samples/monster.fbs`: add generation of binary (.bfbs) schema
Proceeding with version: 1.12.0.177
-- Configuring done
-- Generating done
-- Build files have been written to: /home/Vivas/flatbuffers
And when I run:
$ make
Scanning dependencies of target flatbuffers
[ 1%] Building CXX object CMakeFiles/flatbuffers.dir/src/idl_parser.cpp.o
[ 2%] Building CXX object CMakeFiles/flatbuffers.dir/src/idl_gen_text.cpp.o
[ 3%] Building CXX object CMakeFiles/flatbuffers.dir/src/reflection.cpp.o
[ 4%] Building CXX object CMakeFiles/flatbuffers.dir/src/util.cpp.o
[ 5%] Linking CXX static library libflatbuffers.a
[ 5%] Built target flatbuffers
Scanning dependencies of target flatc
[ 6%] Building CXX object CMakeFiles/flatc.dir/src/idl_parser.cpp.o
[ 7%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_text.cpp.o
[ 9%] Building CXX object CMakeFiles/flatc.dir/src/reflection.cpp.o
[ 10%] Building CXX object CMakeFiles/flatc.dir/src/util.cpp.o
[ 11%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_cpp.cpp.o
[ 12%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_csharp.cpp.o
[ 13%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_dart.cpp.o
[ 14%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_kotlin.cpp.o
[ 15%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_go.cpp.o
[ 17%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_java.cpp.o
[ 18%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_js_ts.cpp.o
[ 19%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_php.cpp.o
[ 20%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_python.cpp.o
[ 21%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_lobster.cpp.o
[ 22%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_lua.cpp.o
[ 23%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_rust.cpp.o
[ 25%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_fbs.cpp.o
[ 26%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_grpc.cpp.o
[ 27%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_json_schema.cpp.o
[ 28%] Building CXX object CMakeFiles/flatc.dir/src/idl_gen_swift.cpp.o
[ 29%] Building CXX object CMakeFiles/flatc.dir/src/flatc.cpp.o
[ 30%] Building CXX object CMakeFiles/flatc.dir/src/flatc_main.cpp.o
[ 31%] Building CXX object CMakeFiles/flatc.dir/src/code_generators.cpp.o
[ 32%] Building CXX object CMakeFiles/flatc.dir/grpc/src/compiler/cpp_generator.cc.o
[ 34%] Building CXX object CMakeFiles/flatc.dir/grpc/src/compiler/go_generator.cc.o
[ 35%] Building CXX object CMakeFiles/flatc.dir/grpc/src/compiler/java_generator.cc.o
[ 36%] Building CXX object CMakeFiles/flatc.dir/grpc/src/compiler/python_generator.cc.o
[ 37%] Building CXX object CMakeFiles/flatc.dir/grpc/src/compiler/swift_generator.cc.o
[ 38%] Building CXX object CMakeFiles/flatc.dir/grpc/src/compiler/ts_generator.cc.o
[ 39%] Linking CXX executable flatc.exe
[ 39%] Built target flatc
Scanning dependencies of target generated_code
[ 40%] Run generation: 'samples/monster.bfbs'
[ 42%] Run generation: 'tests/monster_test_generated.h'
[ 43%] Run generation: 'tests/monster_test.bfbs'
[ 44%] Run generation: 'tests/namespace_test/namespace_test1_generated.h'
[ 45%] Run generation: 'tests/namespace_test/namespace_test2_generated.h'
[ 46%] Run generation: 'tests/union_vector/union_vector_generated.h'
[ 47%] Run generation: 'tests/optional_scalars_generated.h'
[ 48%] Run generation: 'tests/native_type_test_generated.h'
[ 50%] Run generation: 'tests/arrays_test_generated.h'
[ 51%] Run generation: 'tests/arrays_test.bfbs'
[ 52%] Run generation: 'tests/monster_test_bfbs_generated.h'
[ 53%] Run generation: 'tests/monster_extra_generated.h'
[ 54%] Run generation: 'samples/monster_generated.h'
[ 55%] All generated files were updated.
[ 55%] Built target generated_code
Scanning dependencies of target flatsamplebfbs
[ 56%] Building CXX object CMakeFiles/flatsamplebfbs.dir/src/idl_parser.cpp.o
[ 57%] Building CXX object CMakeFiles/flatsamplebfbs.dir/src/idl_gen_text.cpp.o
[ 59%] Building CXX object CMakeFiles/flatsamplebfbs.dir/src/reflection.cpp.o
[ 60%] Building CXX object CMakeFiles/flatsamplebfbs.dir/src/util.cpp.o
[ 61%] Building CXX object CMakeFiles/flatsamplebfbs.dir/samples/sample_bfbs.cpp.o
[ 62%] Linking CXX executable flatsamplebfbs.exe
[ 63%] Built target flatsamplebfbs
Scanning dependencies of target flatsampletext
[ 64%] Building CXX object CMakeFiles/flatsampletext.dir/src/idl_parser.cpp.o
[ 65%] Building CXX object CMakeFiles/flatsampletext.dir/src/idl_gen_text.cpp.o
[ 67%] Building CXX object CMakeFiles/flatsampletext.dir/src/reflection.cpp.o
[ 68%] Building CXX object CMakeFiles/flatsampletext.dir/src/util.cpp.o
[ 69%] Building CXX object CMakeFiles/flatsampletext.dir/samples/sample_text.cpp.o
[ 70%] Linking CXX executable flatsampletext.exe
[ 71%] Built target flatsampletext
Scanning dependencies of target flathash
[ 72%] Building CXX object CMakeFiles/flathash.dir/src/flathash.cpp.o
[ 73%] Linking CXX executable flathash.exe
[ 73%] Built target flathash
Scanning dependencies of target flattests
[ 75%] Building CXX object CMakeFiles/flattests.dir/src/idl_parser.cpp.o
[ 76%] Building CXX object CMakeFiles/flattests.dir/src/idl_gen_text.cpp.o
[ 77%] Building CXX object CMakeFiles/flattests.dir/src/reflection.cpp.o
[ 78%] Building CXX object CMakeFiles/flattests.dir/src/util.cpp.o
[ 79%] Building CXX object CMakeFiles/flattests.dir/src/idl_gen_fbs.cpp.o
[ 80%] Building CXX object CMakeFiles/flattests.dir/tests/test.cpp.o
/home/Vivas/flatbuffers/tests/test.cpp:66:19: error: ‘const auto infinityf’ redeclared as different kind of entity
66 | static const auto infinityf = std::numeric_limits<float>::infinity();
| ^~~~~~~~~
In file included from /usr/lib/gcc/x86_64-pc-cygwin/10/include/c++/cmath:45,
from /home/Vivas/flatbuffers/tests/test.cpp:16:
/usr/include/math.h:398:14: note: previous declaration ‘float infinityf()’
398 | extern float infinityf (void);
| ^~~~~~~~~
In file included from /home/Vivas/flatbuffers/tests/test.cpp:45:
/home/Vivas/flatbuffers/tests/test.cpp: In function ‘void TestMonsterExtraFloats()’:
/home/Vivas/flatbuffers/tests/test.cpp:702:25: error: wrong type argument to unary minus
702 | TEST_EQ(is_quiet_nan(-infinityf), false);
| ^~~~~~~~~
/home/Vivas/flatbuffers/tests/test_assert.h:19:34: note: in definition of macro ‘TEST_EQ’
19 | #define TEST_EQ(exp, val) TestEq(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, "")
| ^~~
/home/Vivas/flatbuffers/tests/test.cpp:731:29: error: wrong type argument to unary minus
731 | TEST_EQ(def_extra->f3(), -infinityf);
| ^~~~~~~~~
/home/Vivas/flatbuffers/tests/test_assert.h:19:39: note: in definition of macro ‘TEST_EQ’
19 | #define TEST_EQ(exp, val) TestEq(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, "")
| ^~~
/home/Vivas/flatbuffers/tests/test.cpp:762:25: error: wrong type argument to unary minus
762 | TEST_EQ(extra->f3(), -infinityf);
| ^~~~~~~~~
/home/Vivas/flatbuffers/tests/test_assert.h:19:39: note: in definition of macro ‘TEST_EQ’
19 | #define TEST_EQ(exp, val) TestEq(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, "")
| ^~~
/home/Vivas/flatbuffers/tests/test.cpp:770:35: error: wrong type argument to unary minus
770 | TEST_EQ(extra->fvec()->Get(1), -infinityf);
| ^~~~~~~~~
/home/Vivas/flatbuffers/tests/test_assert.h:19:39: note: in definition of macro ‘TEST_EQ’
19 | #define TEST_EQ(exp, val) TestEq(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, "")
| ^~~
/home/Vivas/flatbuffers/tests/test.cpp: In function ‘void ValidFloatTest()’:
/home/Vivas/flatbuffers/tests/test.cpp:1971:60: error: wrong type argument to unary minus
1971 | TEST_EQ(TestValue<float>("{ y:-3.4029e+38 }", "float"), -infinityf);
| ^~~~~~~~~
/home/Vivas/flatbuffers/tests/test_assert.h:19:39: note: in definition of macro ‘TEST_EQ’
19 | #define TEST_EQ(exp, val) TestEq(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, "")
| ^~~
/home/Vivas/flatbuffers/tests/test.cpp:2015:53: error: wrong type argument to unary minus
2015 | TEST_EQ(TestValue<float>("{ y:-inf }", "float"), -infinityf);
| ^~~~~~~~~
/home/Vivas/flatbuffers/tests/test_assert.h:19:39: note: in definition of macro ‘TEST_EQ’
19 | #define TEST_EQ(exp, val) TestEq(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, "")
| ^~~
/home/Vivas/flatbuffers/tests/test.cpp:2017:53: error: wrong type argument to unary minus
2017 | TEST_EQ(TestValue<float>(nullptr, "float=-inf"), -infinityf);
| ^~~~~~~~~
/home/Vivas/flatbuffers/tests/test_assert.h:19:39: note: in definition of macro ‘TEST_EQ’
19 | #define TEST_EQ(exp, val) TestEq(exp, val, "'" #exp "' != '" #val "'", __FILE__, __LINE__, "")
| ^~~
/home/Vivas/flatbuffers/tests/test_assert.h: In instantiation of ‘void TestEq(T, U, const char*, const char*, int, const char*) [with T = float; U = float (*)()]’:
/home/Vivas/flatbuffers/tests/test.cpp:730:3: required from here
/home/Vivas/flatbuffers/tests/test_assert.h:92:7: error: invalid ‘static_cast’ from type ‘float’ to type ‘float (*)()’
92 | if (static_cast<U>(expval) != val) {
| ^~~~~~~~~~~~~~~~~~~~~~
make[2]: *** [CMakeFiles/flattests.dir/build.make:184: CMakeFiles/flattests.dir/tests/test.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:247: CMakeFiles/flattests.dir/all] Error 2
make: *** [Makefile:161: all] Error 2
Why is that, and how can I fix it?
Easiest would be to rename infinityf (at tests/test.cpp:66:19) and its uses to something different. If that makes it compile, open a PR on https://github.com/google/flatbuffers with your changes.
It seems like it is clashing with things declared in the cmath header. I am not sure why this happens with cygwin and not on other platform we build for gcc?
Also note this is in the tests, which you don't strictly need to build. Invoking CMake with -DFLATBUFFERS_BUILD_TESTS=OFF would likely also work.