error compiling gamedevframework on ArchLinux ARM with gcc-6.1.1 glibc-2.23-5

[Popolon]

I'm not sure about the part of the system that could be related to this issue ?

The system uses

• gcc 6.1.1
• glibc 2.23-5

[alarm@alarm build]$ make
[ 0%] Building CXX object library/CMakeFiles/gf0.dir/Range.cc.o
/home/alarm/misc/gf/library/Range.cc:31:19: error: duplicate explicit instantiation of 'struct gf::v1::Range' [-fpermissive]
template struct Rangestd::size_t;
^~~~~~~~~~~~~~~~~~
make[2]: *** [library/CMakeFiles/gf0.dir/build.make:327: library/CMakeFiles/gf0.dir/Range.cc.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:118: library/CMakeFiles/gf0.dir/all] Error 2
make: *** [Makefile:128: all] Error 2

[jube]

I think size_t is the same as unsigned on this architecture. Not easy to fix.

[Popolon]

Is there a test that I can made to confirm this ? I use ARMv7 (32 bits), I know that for example, default float format is float not double in QT tool-kit on this platform, and double on x86 and ARMv8 (64 bits).

This can be tested like with this on linux, for both ARM 32bit (v5/v6/v7 I suppose) and ARM 64bit (found in libjpeg-turbo), probably a test for each case is better here. I could at least provide some test/debug on ARMv7, and very probably soon on ARMv8

#if defined GNUC && (defined arm || defined aarch64)

There is some explanation about difference in types on both platforms here:
http://malideveloper.arm.com/downloads/ARMv8_64_bit_migration.pdf

[jube]

You can try to compile something like:

#include <iostream>
#include <type_traits>

int main() {
  std::cout << std::boolalpha;
  std::cout << std::is_same<unsigned, std::size_t>::value << '\n';
  return 0;
}

Compile with gcc -std=c++11 file.cc. If it prints true, then it's the same type.

I see two possible solutions for this bug:

• easy: remove the explicit instantiation for std::size_t (same for Vector, Rect, etc)
• difficult: make a check at build time with CheckTypeSize

I do not really like the preprocessor condition based on architecture because this error may happen on other architectures.

[Popolon]

Answered true. So that's the problem :(.

I didn't coded in C++ since long time and discover lot of evolutions since last time.

[Popolon]

gcc -o test_validation2 -std=c++11 -lstdc++ test_validation.cpp
I needed to type this to compile it, using or not -std=c++11 give the same result.

[jube]

OK. So I will remove the explicit instantiations with std::size_t. Anyway, they are not used in the library. Will come in the next push.