Dear List,
I am currently trying to understand an issue to do with complex number
support in gcc.
Consider the following code:
#include <complex.h>
int main()
{
float _Complex a = _Complex_I;
}
Attempting to compile this with these commands is fine:
$ g++ tmp.cpp -std=gnu++11
$ g++ tmp.cpp
Clang is also fine:
$ clang tmp.cpp -std=c++11
Attempting to compile with c++11 is not:
$ g++ tmp.cpp -std=c ++11
In file included from /usr/include/c++/5/complex.h:36:0,
from tmp.cpp:2:
tmp.cpp: In function ‘int main()’:
tmp.cpp:5:29: error: unable to find numeric literal operator ‘operator""iF’
float _Complex a = _Complex_I;
^
tmp.cpp:5:29: note: use -std=gnu++11 or -fext-numeric-literals to enable
more built-in suffixes
I'm using debian testing's gcc:
$ gcc --version
gcc (Debian 5.2.1-17) 5.2.1 20150911
...
I discussed this on #gcc, and it was suggested (or I misunderstood) that
this is intentional, and the library should not support c-type C++
primitives - however I can find no deprecation notice for this, nor does
it appear that the c++11 standard (as far as I can see from a quick
skim) has changed the behaviour in this regard.
Is this intended behaviour, or is this a bug? This behaviour was noticed
when troubleshooting compilation behaviours in mathgl.
https://groups.google.com/forum/?_escaped_fragment_=topic/mathgl/cl4uYygPmOU#!topic/mathgl/cl4uYygPmOU
Thanks.
