#1726 Do not use std::complex<ft> unless ft is float/double/long double in tests
Metadata
| Property | Value |
|---|---|
| Reported by | Elias Pipping (elias.pipping@fu-berlin.de) |
| Reported at | Oct 25, 2015 08:05 |
| Type | Bug Report |
| Version | Git (pre3.0) |
| Operating System | Unspecified / All |
Description
I'm on a machine with the system compiler
gcc (Debian 4.9.2-10) 4.9.2
on which I use
clang version 3.7.0 (tags/RELEASE_370/final)
that I compiled myself and which uses the libstdc++ provided by the aforementioned gcc.
Dune determines that this compiler supports C++14/C++1y because the snippet
#include <memory>
int main() {
std::make_unique<int>();
}from cmake/modules/CheckCXXFeatures.cmake compiles. In fact, not all is well, though: If you take the piece of code
#include <complex>
int
main()
{
std::complex<int> const x(1,2);
int r = x.real();
}this compiles with 'clang++ -std=c++11' but not with 'clang++ -std=c++14'. In the latter case, I get the error
foo.cc:7:13: error: no matching member function for call to 'real'
int r = x.real();
~~^~~~
/usr/lib/gcc/x86_64-linux-gnu/4.9/../../../../include/c++/4.9/complex:144:7: note:
candidate function not viable: 'this' argument has type 'const std::complex<int>',
but method is not marked const
real() { return _M_real; }
^The relevant lines here are:
143 constexpr _Tp
144 real() { return _M_real; }I came across this problem because it makes dune-common's fvectortest fail in the same way here:
dune/common/densevector.hh:77:16: error: no matching
member function for call to 'real'
return c.real()*c.real() + c.imag()*c.imag();I can think of at least two ways to address this:
- catch this issue in dune-common's C++1y feature check. The patch I've attached does the trick (maybe there's a nicer way to split this check into two separate memory/complex checks and maybe there's a way to avoid the code duplication, too).
- Allow the user to selectively disable C++14 or C++1y (yet keep using C++11). Currently, I only see a way to disable all checks for C++ features; because dune relies on C++11, the check for which is disabled, too, though, that doesn't seem very useful.