[Boost-bugs] [Boost C++ Libraries] #3183: Compilation fails with many arguments, with default values

Subject: [Boost-bugs] [Boost C++ Libraries] #3183: Compilation fails with many arguments, with default values
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-06-16 04:06:32

#3183: Compilation fails with many arguments, with default values
---------------------------------------------------------+------------------
 Reporter:  Christopher A. Mejia <camejia_at_[hidden]>  |       Owner:         
     Type:  Bugs                                         |      Status:  new    
Milestone:  Boost 1.40.0                                 |   Component:  None   
  Version:  Boost 1.39.0                                 |    Severity:  Problem
 Keywords:                                               |  
---------------------------------------------------------+------------------
 Hi,

 I'm using pyplusplus and Boost.Python to wrap a class where one of the
 member functions has many (28) arguments, most of them with default
 values.  The wrapping code handles the default arguments with the Py++ "do
 nothing" approach, i.e. not by using the
 BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS macro.  I am using bjam to build my
 project, and am confident that the code produced by Py++ should compile,
 because the other member functions with similar (but fewer) arguments and
 default arguments compile fine.  I did have to increase
 BOOST_PYTHON_MAX_ARITY, and I am sure it is large enough to cover my
 arguments.

 I suspect I am running into a compiler limitation because I get a slightly
 different error message when I remove the -ftemplate-depth-128 flag (the
 error message appears to be truncated when I have the -ftemplate-depth-18
 flag).  Here is the essence of the error message, without the -ftemplate-
 depth-128 flag:
 -------------------
 /data/cmejia/install/boost_1_39_0/boost/python/detail/invoke.hpp: In
 function `PyObject* boost::python::detail::invoke(...
 /data/cmejia/install/boost_1_39_0/boost/python/detail/caller.hpp:223:
 instantiated from `PyObject* ...
 /data/cmejia/install/boost_1_39_0/boost/python/object/py_function.hpp:38:
 instantiated from `PyObject* ...
 dcs.cpp:9:   instantiated from here
 /data/cmejia/install/boost_1_39_0/boost/python/detail/invoke.hpp:75:
 error: must use .* or ->* to call pointer-to-member function in `f (...)'
 -------------------
 Which doesn't make sense because none of the other code has needed to use
 .* or ->*.

 The last 19 arguments to this member function are all doubles, all with
 default values.  If I remove the last 3 doubles from the wrapping code
 produced by pyplusplus, *and* remove them from the header file I am trying
 to wrap, I am able to compile successfully.  (If I remove them only from
 my wrapping code, but not from the header file I am trying to wrap, I am
 unable to compile.)  Anyway, this seems to indicate that the compiler is
 running up against some limit, and I was wondering if there was a flag to
 set to get past this problem.  The current set of compiler flags, from
 bjam, are

 "g++"  -ftemplate-depth-128 -O0 -fno-inline -Wall -g -fPIC
 -DBOOST_PYTHON_MAX_ARITY=40

 I am using g++ version 3.4.6 on Red Hat Enterprise Linux WS release 4
 (Nahant Update 6).  Any information would be appreciated.

 (follow up...):

 I developed a minimal complete test case
 exhibiting this problem, contained in the attached files.  The compilation
 command I used was:

 g++ -DBOOST_PYTHON_MAX_ARITY=40 -I/data/cmejia/install/boost_1_39_0
 -I/data/include/python2.6
  -c -o foo.o foo.cpp

 As I explained earlier in the first message of this thread, this fails to
 compile, but if I remove one double argument towards the end (i.e. edit
 out one line of foo.hpp and two lines of foo.cpp) it does compile
 successfully.  The file foo.pp is the preprocessed source from "g++ ... -E
 foo.cpp > foo.pp".  I would appreciate any further insight into this
 problem, and hopefully we can use this test case to make Boost.Python an
 even better tool.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3183>
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