[GRASS-dev] [GRASS GIS] #2871: lib/iostream/mm.cpp:Fails to build with GCC 6: declaration of ... has a different exception specifier

GRASS GIS trac at osgeo.org
Thu Jun 30 12:56:42 PDT 2016

#2871: lib/iostream/mm.cpp:Fails to build with GCC 6: declaration of ... has a
different exception specifier
  Reporter:  sebastic    |      Owner:  grass-dev@…
      Type:  defect      |     Status:  new
  Priority:  blocker     |  Milestone:  7.2.0
 Component:  Compiling   |    Version:  svn-releasebranch70
Resolution:              |   Keywords:  iostream, gcc, -fexceptions, throw,
                         |  noexcept
       CPU:  All         |   Platform:  Linux
Changes (by wenzeslaus):

 * keywords:  iostream => iostream, gcc, -fexceptions, throw, noexcept


 The GCC message is pretty confusing because it points to two places with
 the same specification claiming that the specification is different and
 showing previous declaration coming from library I suppose. Anyway, it
 seems that it all depends on the version of the standard used. C++11 and
 higher wants no specifiers (they are depreciated in C++) while C++98
 standard with GCC option `-fexceptions` requires them. I don't know how to
 explain that the standard drafts around C++ don't specify `noexcept` for
 `delete operator` but there is no difference when using GCC 5.2 with
 -std=c++11 or -std=c++14; perhaps the library version is the same. I used
 `__cplusplus` to figure out the C++ standard in use, it seems that it is
 good enough (for g++ and clang).

 The graph in the Debian bug report says 7.0.4, so this means that we need
 to eventually backport it to 70 unless they switch to 72. Can somebody
 conveniently test it with GCC 6?

 Here are my references:

 * https://gcc.gnu.org/gcc-6/changes.html: The default mode for C++ is now
 `-std=gnu++14` instead of `-std=gnu++98`.
 * http://en.cppreference.com/w/cpp/preprocessor/replace: `__cplusplus`:
 denotes the version of C++ standard that is being used, expands to value
 `199711L` (until C++11), `201103L` (C++11), or `201402L` (C++14)
 * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1905.pdf
  * `void* operator new(std::size_tsize) throw(std::bad_alloc);`
  * `void operator delete(void* ptr) throw();`
  * ...
 * http://www.open-std.org/Jtc1/sc22/wg21/docs/papers/2011/n3242.pdf and
  * `void* operator new(std::size_t);`
  * `void operator delete(void*);`
 * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/n4594.pdf
  * `void* operator new(std::size_t size);`
  * `void operator delete(void* ptr) noexcept;`
  * ...

Ticket URL: <https://trac.osgeo.org/grass/ticket/2871#comment:16>
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