Build issues on QNX 7.0

[dschopf]

What version of protobuf and what language are you using?
Version: v3.16.0
Language: C++

What operating system (Linux, Windows, ...) and version?
QNX 7.0 build on Ubuntu 20.04

What runtime / compiler are you using (e.g., python version or gcc version)
GCC 5.4.0

What did you do?
Steps to reproduce the behavior:
Check out v3.16.0
Run CC=qcc CXX=q++ ./configure --host aarch64-qnx-gnu && make

What did you expect to see
Build succeeds

What did you see instead?
Build fails

First, there are many errors about #include <endian.h>, which is not available on QNX.
This can be fixed with the following patch which also adds support for 64 bit builds:

diff --git a/src/google/protobuf/io/coded_stream.h b/src/google/protobuf/io/coded_stream.h
index b6c11d27a..1cf006832 100644
--- a/src/google/protobuf/io/coded_stream.h
+++ b/src/google/protobuf/io/coded_stream.h
@@ -136,8 +136,10 @@
 #elif defined(__FreeBSD__)
 #include <sys/endian.h>  // __BYTE_ORDER
 #else
+#if !defined(__QNX__)
 #include <endian.h>  // __BYTE_ORDER
 #endif
+#endif
 #if ((defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)) ||    \
      (defined(__BYTE_ORDER) && __BYTE_ORDER == __LITTLE_ENDIAN)) && \
     !defined(PROTOBUF_DISABLE_LITTLE_ENDIAN_OPT_FOR_TEST)
diff --git a/src/google/protobuf/stubs/platform_macros.h b/src/google/protobuf/stubs/platform_macros.h
index ce1b1e365..6d8135755 100644
--- a/src/google/protobuf/stubs/platform_macros.h
+++ b/src/google/protobuf/stubs/platform_macros.h
@@ -46,7 +46,11 @@
 #define GOOGLE_PROTOBUF_ARCH_32_BIT 1
 #elif defined(__QNX__)
 #define GOOGLE_PROTOBUF_ARCH_ARM_QNX 1
+#if defined(aarch64)
+#define GOOGLE_PROTOBUF_ARCH_64_BIT 1
+#else
 #define GOOGLE_PROTOBUF_ARCH_32_BIT 1
+#endif
 #elif defined(_M_ARM) || defined(__ARMEL__)
 #define GOOGLE_PROTOBUF_ARCH_ARM 1
 #define GOOGLE_PROTOBUF_ARCH_32_BIT 1
diff --git a/src/google/protobuf/stubs/port.h b/src/google/protobuf/stubs/port.h
index 0f3b5aa62..a64101862 100644
--- a/src/google/protobuf/stubs/port.h
+++ b/src/google/protobuf/stubs/port.h
@@ -62,8 +62,10 @@
 #elif defined(__FreeBSD__)
 #include <sys/endian.h>  // __BYTE_ORDER
 #else
+#if !defined(__QNX__)
 #include <endian.h>  // __BYTE_ORDER
 #endif
+#endif
 #if ((defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)) ||   \
      (defined(__BYTE_ORDER) && __BYTE_ORDER == __LITTLE_ENDIAN) || \
      (defined(BYTE_ORDER) && BYTE_ORDER == LITTLE_ENDIAN)) &&      \

Once this is fixed, there are additional errors due to -std=c++11being used instead of -std=gnu++11, which I could fix like this

diff --git a/configure.ac b/configure.ac
index 6251e37f3..7627152d0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -93,7 +93,7 @@ AS_IF([test "x${ac_cv_env_CXXFLAGS_set}" = "x"],[
   # Protocol Buffers contains several checks that are intended to be used only
   # for debugging and which might hurt performance.  Most users are probably
   # end users who don't want these checks, so add -DNDEBUG by default.
-  CXXFLAGS="$CXXFLAGS -std=c++11 -DNDEBUG"
+  CXXFLAGS="$CXXFLAGS -std=gnu++11 -DNDEBUG"

   AC_MSG_RESULT([use default: $PROTOBUF_OPT_FLAG $CXXFLAGS])
 ],[

But for the final error, I am not sure, since this also happens in the generated code:

google/protobuf/descriptor.pb.cc: In constructor 'constexpr google::protobuf::SourceCodeInfo_Location::SourceCodeInfo_Location(google::protobuf::internal::ConstantInitialized)':
google/protobuf/descriptor.pb.cc:401:88: error: call to non-constexpr function 'std::__1::atomic<_Tp>::atomic() [with _Tp = int]'
   , trailing_comments_(&::PROTOBUF_NAMESPACE_ID::internal::fixed_address_empty_string){}
                                                                                        ^
In file included from ./google/protobuf/io/coded_stream.h:115:0,
                 from ./google/protobuf/descriptor.pb.h:23,
                 from google/protobuf/descriptor.pb.cc:4:
/opt/toolchains/qnx700/target/qnx7/usr/include/c++/v1/atomic:1008:5: note: 'std::__1::atomic<_Tp>::atomic() [with _Tp = int]' is not usable as a constexpr function because:
     atomic() _NOEXCEPT _LIBCPP_DEFAULT
     ^
/opt/toolchains/qnx700/target/qnx7/usr/include/c++/v1/atomic:927:5: note: defaulted constructor calls non-constexpr 'std::__1::__atomic_base<_Tp, true>::__atomic_base() [with _Tp = int]'
     __atomic_base() _NOEXCEPT _LIBCPP_DEFAULT
     ^
/opt/toolchains/qnx700/target/qnx7/usr/include/c++/v1/atomic:927:5: note: 'std::__1::__atomic_base<_Tp, true>::__atomic_base() [with _Tp = int]' is not usable as a constexpr function because:
/opt/toolchains/qnx700/target/qnx7/usr/include/c++/v1/atomic:900:5: note: defaulted constructor calls non-constexpr 'std::__1::__atomic_base<_Tp, <anonymous> >::__atomic_base() [with _Tp = int; bool <anonymous> = false]'
     __atomic_base() _NOEXCEPT = default;
     ^
/opt/toolchains/qnx700/target/qnx7/usr/include/c++/v1/atomic:900:5: note: 'std::__1::__atomic_base<_Tp, <anonymous> >::__atomic_base() [with _Tp = int; bool <anonymous> = false]' is not usable as a constexpr function because:
/opt/toolchains/qnx700/target/qnx7/usr/include/c++/v1/atomic:562:3: note: defaulted constructor calls non-constexpr 'std::__1::__gcc_atomic::__gcc_atomic_t<_Tp>::__gcc_atomic_t() [with _Tp = int]'
   __gcc_atomic_t() _NOEXCEPT {}
   ^
google/protobuf/descriptor.pb.cc: In constructor 'constexpr google::protobuf::GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(google::protobuf::internal::ConstantInitialized)':
google/protobuf/descriptor.pb.cc:429:13: error: call to non-constexpr function 'std::__1::atomic<_Tp>::atomic() [with _Tp = int]'
   , end_(0){}
             ^
cc: /opt/toolchains/qnx700/host/linux/x86_64/usr/lib/gcc/i586-pc-nto-qnx7.0.0/5.4.0/cc1plus error 1

The following patch fixes this as well:

diff --git a/src/google/protobuf/descriptor.pb.cc b/src/google/protobuf/descriptor.pb.cc
index c22ae431c..4df886ab6 100644
--- a/src/google/protobuf/descriptor.pb.cc
+++ b/src/google/protobuf/descriptor.pb.cc
@@ -393,9 +393,9 @@ PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT UninterpretedOptionDefaultTypeI
 constexpr SourceCodeInfo_Location::SourceCodeInfo_Location(
   ::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized)
   : path_()
-  , _path_cached_byte_size_()
+  , _path_cached_byte_size_(0)
   , span_()
-  , _span_cached_byte_size_()
+  , _span_cached_byte_size_(0)
   , leading_detached_comments_()
   , leading_comments_(&::PROTOBUF_NAMESPACE_ID::internal::fixed_address_empty_string)
   , trailing_comments_(&::PROTOBUF_NAMESPACE_ID::internal::fixed_address_empty_string){}
@@ -423,7 +423,7 @@ PROTOBUF_ATTRIBUTE_NO_DESTROY PROTOBUF_CONSTINIT SourceCodeInfoDefaultTypeIntern
 constexpr GeneratedCodeInfo_Annotation::GeneratedCodeInfo_Annotation(
   ::PROTOBUF_NAMESPACE_ID::internal::ConstantInitialized)
   : path_()
-  , _path_cached_byte_size_()
+  , _path_cached_byte_size_(0)
   , source_file_(&::PROTOBUF_NAMESPACE_ID::internal::fixed_address_empty_string)
   , begin_(0)
   , end_(0){}

Am I supposed to fix this manually for all .pb.cc files or could this be fixed more generally?

And finally there is a linker error, which I don't care about because I can run protoc on my host system:

/opt/toolchains/qnx700/host/linux/x86_64/usr/bin/i586-pc-nto-qnx7.0.0-ld: .libs/protoc: hidden symbol `__moddi3' in /opt/toolchains/qnx700/host/linux/x86_64/usr/lib/gcc/i586-pc-nto-qnx7.0.0/5.4.0/pic/libgcc.a(_moddi3.o) is referenced by DSO
/opt/toolchains/qnx700/host/linux/x86_64/usr/bin/i586-pc-nto-qnx7.0.0-ld: final link failed: Bad value
cc: /opt/cinemo/toolchains/qnx700/host/linux/x86_64/usr/bin/i586-pc-nto-qnx7.0.0-ld error 1

[haberman]

Feel free to send a PR for these fixes.

The codegen fixes can be made in the code generator, for example:

protobuf/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc

Line 489 in 3f5fc4d

format("\n, _$name$_cached_byte_size_()");

protobuf/src/google/protobuf/compiler/cpp/cpp_enum_field.cc

Line 499 in 3f5fc4d

format("\n, _$name$_cached_byte_size_()");

Which errors did you get that require -std=gnu++11?

[dschopf]

The errors which require -std=gnu++11 are these:

google/protobuf/io/zero_copy_stream_impl.cc: In function 'int google::protobuf::io::{anonymous}::close_no_eintr(int)':
google/protobuf/io/zero_copy_stream_impl.cc:76:22: error: 'close' was not declared in this scope
     result = close(fd);
                      ^
google/protobuf/io/zero_copy_stream_impl.cc: In member function 'virtual int google::protobuf::io::FileInputStream::CopyingFileInputStream::Read(void*, int)':
google/protobuf/io/zero_copy_stream_impl.cc:136:38: error: 'read' was not declared in this scope
     result = read(file_, buffer, size);
                                      ^
google/protobuf/io/zero_copy_stream_impl.cc: In member function 'virtual int google::protobuf::io::FileInputStream::CopyingFileInputStream::Skip(int)':
google/protobuf/io/zero_copy_stream_impl.cc:150:61: error: 'lseek' was not declared in this scope
   if (!previous_seek_failed_ && lseek(file_, count, SEEK_CUR) != (off_t)-1) {
                                                             ^
google/protobuf/io/zero_copy_stream_impl.cc: In member function 'virtual bool google::protobuf::io::FileOutputStream::CopyingFileOutputStream::Write(const void*, int)':
google/protobuf/io/zero_copy_stream_impl.cc:218:77: error: 'write' was not declared in this scope
       bytes = write(file_, buffer_base + total_written, size - total_written);
                                                                             ^
google/protobuf/io/zero_copy_stream_impl.cc: In member function 'virtual int google::protobuf::io::FileInputStream::CopyingFileInputStream::Skip(int)':
google/protobuf/io/zero_copy_stream_impl.cc:163:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

It looks like there are some defines which accomplish the same while still using -std=c++11, I will have to check.

Yes, defining _XOPEN_SOURCE fixes these issues for me with -std=c++11.

[deannagarcia]

Closing since the PR to fix has already been merged.