Qt 5.10.0 compile with clang on ubuntu 17.10

osmial

Hi all,

cause I'm going to develop mobile app using Qt I want to recompile Qt sources using clang due to Google's decision to get rid of GCC support in Android's NDK. But as a first step I just want to compile Qt for desktop ubuntu 17.10 using clang.
I have installed clang 5.0

My configure command:

../configure -c++std c++1z -platform linux-clang -opensource -nomake examples -nomake tests

Unfortunately it fails with error:
ERROR: C++11 <random> is required and is missing or failed to compile.
in output messages I can also find:

Checking for C++14 support... yes
Checking for C++1z support... yes
...
Checking for C++11 <future>... no
Checking for C++11 <random>... no

which makes me quite confused... but output message encourages to check out config.log file for details, so:

executing config test cxx11_random
+ cd /home/tomek/workspace/qt-dev/qt5/build-5.10.0_x86_64_clang/config.tests/unix/cxx11_random && /home/tomek/workspace/qt-dev/qt5/build-5.10.0_x86_64_clang/qtbase/bin/qmake "CONFIG -= qt debug_and_release app_bundle lib_bundle" "CONFIG += shared use_gold_linker warn_off console single_arch" /home/tomek/workspace/qt-dev/qt5/qtbase/config.tests/unix/cxx11_random
+ cd /home/tomek/workspace/qt-dev/qt5/build-5.10.0_x86_64_clang/config.tests/unix/cxx11_random && MAKEFLAGS= /usr/bin/make
> clang++ -c -pipe -O2 -w -fPIC  -I/home/tomek/workspace/qt-dev/qt5/qtbase/config.tests/unix/cxx11_random -I. -I/home/tomek/workspace/qt-dev/qt5/qtbase/mkspecs/linux-clang -o cxx11_random.o /home/tomek/workspace/qt-dev/qt5/qtbase/config.tests/unix/cxx11_random/cxx11_random.cpp
> In file included from /home/tomek/workspace/qt-dev/qt5/qtbase/config.tests/unix/cxx11_random/cxx11_random.cpp:29:
> In file included from /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/random:35:
> /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/bits/c++0x_warning.h:32:2: error: This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
> #error This file requires compiler and library support \
>  ^
> /home/tomek/workspace/qt-dev/qt5/qtbase/config.tests/unix/cxx11_random/cxx11_random.cpp:33:5: error: use of undeclared identifier 'std'
>     std::mt19937 mt(0);
>     ^
> 2 errors generated.

and second similar log about c++11_future test.
As log says there is no -std=c++11 or -std=gnu++11 option specified, which can be confirmed few lines above. But I've specified -c++std c++1z option for configure script which should satisfy that build command...
That make me think there might be a bug somewhere in build system but before I create a ticket I want to ask if anybody see if I'm doing something wrong, or maybe somebody has already observed the same issue?

Thanks in advance,
osmial

6thC

I use QMake and use things like:

CONFIG += c++17

Perhaps try c++17 instead of c++1z - https://clang.llvm.org/cxx_status.html

C++17 implementation status
Clang 5 and later implement all the features of the C++ 2017 Draft International Standard.

You can use Clang in C++17 mode with the -std=c++17 option (use -std=c++1z in Clang 4 and earlier).

osmial

Yes, that's next interesting thing I forgot to mention about in first post.
When I'm trying with -c++std c++17 (passing this flag to configure script) the output ends with:

ERROR: Invalid argument c++17 to command line parameter c++std

> clang++ -v
clang version 5.0.0-3 (tags/RELEASE_500/final)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/7
Found candidate GCC installation: /usr/bin/../lib/gcc/i686-linux-gnu/7.2.0
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.1
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/6.4.0
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/7.2.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.1
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.2.0
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0
Candidate multilib: .;@m64
Selected multilib: .;@M64

Anybody has tried building latest releases with clang?

jsulm

@osmial said in Qt 5.10.0 compile with clang on ubuntu 17.10:

c++17

Then try with c++14

osmial

I've started without passing this flag to configure script at all. But it failed. Then I've started to experiment with versions - I've tried all from c++11 to c++17.
For flags c++11 - c++1z output is build error, for c++17 it says this argument is being not recognized.

jsulm

@osmial And what about c++14?

osmial

By writing c++11 - c++1z I was thinking about range:
c++11, c++14, c++1z:
ERROR: C++11 <random> is required and is missing or failed to compile.

for c++17:
ERROR: Invalid argument c++17 to command line parameter c++std