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Boost.MultiIndex Compiler specifics



Boost.MultiIndex has been tried in different compilers, with various degrees of success. We list the limitations encountered, along with suitable workarounds when available.

Contents

Borland C++ Builder 6.4 and later

Currently, Boost.MultiIndex cannot be used with any of BCB 6.4 up to BCB 2006 and CodeGear C++Builder 2009. The number of problems encountered during the tests makes it unlikely that future versions of the library can be made to work under these compilers.

Comeau C/C++ 4.3.10.1 for Windows (VC++ 9.0 backend)

Note: Last tested in Boost 1.38. The information might be no longer accurate.

No problems have been detected with this compiler. The library fails to compile, however, when Microsoft Visual C++ 6.0 is used as the backend. Last time they were tested (Boost.1.34.1), VC++ 7.0/7.1 backends worked correctly. The beta 2 version of the Comeau compiler 4.3.10.1 has been used.

Compaq C++ 6.5-042 and later for Tru64 UNIX

Note: Last tested in Boost 1.38. The information might be no longer accurate.

No problems have been detected with this compiler. Last tested for version 7.1-006.

GNU GCC 3.2 and later

No problems have been detected with several versions of this compiler starting from 3.2. The following versions have been explicitly tested:

Boost.MultiIndex does not work with versions 3.1 and prior of GCC.

GNU GCC for Tru64 UNIX

On this platform, GCC is not able to handle debug symbol names whose length exceeds 32,768 bytes, resulting in the error mips-tfile, ... string too big. You may encounter this issue with heavily templatized code like Boost.MultiIndex, which typically produces long symbol names. The problem can be overcome by omitting the compiler option -g (generate debugging information.) Alternatively, consult the section on reduction of symbol name lengths for various applicable workarounds.

Darwin GCC 4.0

Build 4061 of GCC 4.0, shipped with Darwin 8.2 and prior (Mac OS X 10.4.2 and prior), corresponds to a prerelease version of GNU GCC 4.0.0 which introduces a regression bug related to binding of references to temporary objects. This bug precludes the usage of Boost.MultiIndex invariant-checking mode; other than this, Boost.MultiIndex works correctly. The bug is corrected in GCC 4.0 Apple build 5026, which is in sync with the official release of GNU GCC 4.0.0, so the invariant-checking mode is available from this upgrade.

HP aC++ A.06.12 and later for HP-UX IA64

Note: Last tested in Boost 1.38. The information might be no longer accurate.

No problems have been detected with this compiler. Last tested for version A.06.17.

HP aC++ A.03.80 for HP-UX PA-RISC

Note: Last tested in Boost 1.38. The information might be no longer accurate.

No problems have been detected with this compiler. Last tested for version A.03.85.

IBM VisualAge C++ V6.0 for AIX

Note: Last tested in Boost 1.33.1. The information might be no longer accurate.


member not supported, refer to the section on use of member_offset for workarounds. member_offset causes the compiler to emit warnings about the use of offsetof with non-POD types: these warnings can be suppressed by setting the compiler option -qsuppress=1540-1281, or, alternatively, by inserting the following preprocessor directive:

#pragma info(nolan)

This latter pragma, however, may also eliminate other warnings not related to the use of offsetof.


Serialization capabilities are not available as Boost.Serialization is not supported on this platform.

IBM XL C/C++ V9.0 for AIX and later

member not supported, refer to the section on use of member_offset for workarounds. member_offset causes the compiler to emit warnings about the use of offsetof with non-POD types: these warnings can be suppressed by setting the compiler option -qsuppress=1540-1281, or, alternatively, by inserting the following preprocessor directive:

#pragma info(nolan)

This latter pragma, however, may also eliminate other warnings not related to the use of offsetof. Other than this, Boost.MultiIndex works without problems. Last tested for version V10.1.

Intel C++ Compiler for Linux 8.1 and later

No problems have been detected with this compiler. Last tested for compiler versions 9.0 to 11.0.

Intel C++ Compiler for Mac OS 9.1 and later

No problems have been detected with this compiler. Tested from version 9.1 to 10.1.

Intel C++ Compiler for Windows 32-bit 8.0 and later

When used on top of MSVC++ 7.0 or prior, argument dependent lookup is disabled by default. This will cause problems with many Boost libraries, and in particular with the serialization part of Boost.MultiIndex. Argument dependent lookup is enabled by adding /Qoption,c,--arg_dep_lookup to the project options. Other than this, Boost.MultiIndex works without problems. Last tested for compiler version 11.0.

Intel C++ Compiler for Windows 64-bit 10.0 and later

Note: Last tested in Boost 1.38. The information might be no longer accurate.

No problems have been detected with this compiler. Last tested for compiler versions 10.1 to 11.0.

Metrowerks CodeWarrior 8.3

Note: Last tested in Boost 1.36. The information might be no longer accurate.

Predefined key extractors instantiated on a given type do not accept objects of derived types. For instance:

struct base{};
struct derived:public base{};
...

identity<base> key_extractor;
derived        x;

// not accepted by this compiler: an explicit cast to base is required
key_extractor(x);

Other than this, Boost.MultiIndex works without problems under Mac OS and Windows (last tested under Windows only).

Metrowerks CodeWarrior 9 and later

Note: Last tested in Boost 1.34.1. The information might be no longer accurate.

Boost.MultiIndex works correctly with versions of this compiler from 9.0 to 9.5, both under Mac OS and Windows.

Microsoft Visual C++ 6.0 Service Pack 5

Note: Last tested in Boost 1.36. The information might be no longer accurate.


Beginning with Boost.1.36, Boost.Serialization is no longer supported in this compiler, thus the serialization capabilities cannot be used.


member not supported, refer to the section on use of member_offset for workarounds.

const_mem_fun and mem_fun not supported, refer to the section on use of const_mem_fun_explicit and mem_fun_explicit for workarounds.


No support for index retrieval and projection nested types and member functions:

You can use instead their global equivalents. Also, this compiler does not implement argument dependent lookup, so you might need to explicitly qualify these global names with ::boost::multi_index.


boost::multi_index::multi_index_container is imported to namespace boost by means of a using declaration. MSVC++ 6.0, however, does not properly handle this import. So, instead of writing:

boost::multi_index_container<...>

use the following:

boost::multi_index::multi_index_container<...>

or else resort to a directive using namespace boost::multi_index.


The lack of partial template specialization support in MSVC++ 6.0 results in some inconveniences when using composite_key that can be remedied as explained in "composite_key in compilers without partial template specialization".


Due to problems with function template ordering support, composite_key_compare and related classes do not accept the notational variations of operator() where one of the operands is treated as if included into a tuple of length 1. As a result, the user cannot ever omit tuple enclosing when specifying the arguments of lookup operations involving composite keys.


Predefined key extractors instantiated on a given type do not accept objects of derived types. For instance:

struct base{};
struct derived:public base{};
...

identity<base> key_extractor;
derived        x;

// not accepted by this compiler: an explicit cast to base is required
key_extractor(x);

MSVC++ 6.0 presents serious limitations for the maximum length of symbol names generated by the compiler, which might result in the linker error LNK1179: invalid or corrupt file: duplicate comdat comdat. To overcome this problem, consult the section on reduction of symbol name lengths for various applicable workarounds.


Under some circumstances, the compiler emits the error C2587: '_U' : illegal use of local variable as default parameter, inside the MSVC internal header <xlocnum>. This problem is a recurrent bug of the compiler, and has been reported in other unrelated libraries, like the Boost Graph Library, Boost.MultiArray, Boost.Regex, CGAL and MySQL++. The error is triggered, though not in a systematic manner, by the use of multi_index_container iterator constructor. Two workarounds exist: the first consists of avoiding this constructor and replacing code like:

multi_index_container<...> s(c.begin(),c.end());

with equivalent operations:

multi_index_container<...> s;
s.insert(c.begin(),c.end());

The second workaround has not been confirmed by the author, but it is given on the Internet in connection with this error appearing in other libraries. Replace line 84 of <xlocnum>

 #define _VIRTUAL	virtual

with the following:

 #define _VIRTUAL

Warning: it is not known whether this replacement can result in unexpected side effects in code implicitly using <xlocnum>.


In general, the extensive use of templates by Boost.MultiIndex puts this compiler under severe stress, so that several internal limitations may be reached. The following measures can help alleviate these problems:

Microsoft Visual C++ 6.0 Service Pack 5 + STLport 4.5.3 and later

Note: Last tested in Boost 1.36. The information might be no longer accurate.

Boost.MultiIndex works for this configuration. The same limitations apply as in MSVC++ 6.0 with its original Dinkumware standard library. STLport 4.6.2 and 5.0.1 has also been confirmed to work correctly.

Microsoft Visual C++ 7.0

Note: Last tested in Boost 1.35. The information might be no longer accurate.


Beginning with Boost.1.36, Boost.Serialization is no longer supported in this compiler, thus the serialization capabilities cannot be used.


member not supported, refer to the section on use of member_offset for workarounds.


No support for index retrieval and projection nested types and member functions:

You can use instead their global equivalents. Also, this compiler does not implement argument dependent lookup, so you might need to explicitly qualify these global names with ::boost::multi_index.


boost::multi_index::multi_index_container is imported to namespace boost by means of a using declaration. MSVC++ 7.0, however, does not properly handle this import. So, instead of writing:

boost::multi_index_container<...>

use the following:

boost::multi_index::multi_index_container<...>

or else resort to a directive using namespace boost::multi_index.


The lack of partial template specialization support in MSVC++ 7.0 results in some inconveniences when using composite_key that can be remedied as explained in "composite_key in compilers without partial template specialization".


Due to problems with function template ordering support, composite_key_compare and related classes do not accept the notational variations of operator() where one of the operands is treated as if included into a tuple of length 1. As a result, the user cannot ever omit tuple enclosing when specifying the arguments of lookup operations involving composite keys.


Predefined key extractors instantiated on a given type do not accept objects of derived types. For instance:

struct base{};
struct derived:public base{};
...

identity<base> key_extractor;
derived        x;

// not accepted by this compiler: an explicit cast to base is required
key_extractor(x);

Microsoft Visual C++ 7.0 + STLport 5.0.1

Note: Last tested in Boost 1.35. The information might be no longer accurate.

Boost.MultiIndex works for this configuration. The same issues apply as in MSVC++ 7.0 with its original Dinkumware standard library.

Microsoft Visual C++ 7.1

Problems have been reported when compiling the library with the /Gm option (Enable Minimal Rebuild.) Seemingly, this is due to an internal defect of the compiler (see for instance this mention of a similar issue in the Boost Users mailing list.) If /Gm is turned off, Boost.MultiIndex compiles and runs without further problems.

Microsoft Visual C++ 8.0 and later

No problems have been detected with this compiler, both in 32-bit and 64-bit modes. Last tested for compiler versions 8.0 and 9.0.

Sun Studio 10 and later for Solaris

No problems have been detected with this platform. The exact compiler versions tested were:

The option -library=stlport4 was used to replace the default standard library with STLport.

Portability techniques

Use of member_offset

The member key extractor poses some problems in compilers that do not properly support pointers to members as non-type template arguments, as indicated by the Boost Configuration Library defect macro BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS. The following compilers have been confirmed not to work correctly with member:

This program can help determine if your compiler properly supports pointers to members as non-type template parameters:

#include <iostream>

struct pair
{
  int x,y;

  pair(int x_,int y_):x(x_),y(y_){}
};

template<int pair::* PtrToPairMember>
struct foo
{
  int bar(pair& p){return p.*PtrToPairMember;}
};

int main()
{
  pair p(0,1);
  foo<&pair::x> fx;
  foo<&pair::y> fy;

  if(fx.bar(p)!=0||fy.bar(p)!=1)std::cout<<"KO"<<std::endl;
  else std::cout<<"OK"<<std::endl;

  return 0;
}

If you find a compiler that does not pass the test, and for which BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS is not defined, please report to the Boost developers mailing list.

To overcome this defect, a replacement utility member_offset has been provided that does the work of member at the expense of less convenient notation and the possibility of non-conformance with the standard. Please consult the reference for further information on member_offset. As an example of use, given the class

class A
{
  int x;
}

the instantiation member<A,int,&A::x> can be simulated then as member_offset<A,int,offsetof(A,x)>.

For those writing portable code, Boost.MultiIndex provides the ternary macro BOOST_MULTI_INDEX_MEMBER. Continuing with the example above, the expression

BOOST_MULTI_INDEX_MEMBER(A,int,x)

expands by default to

member<A,int,&A::x>

or alternatively to

member_offset<A,int,offsetof(A,x)>

if BOOST_NO_POINTER_TO_MEMBER_TEMPLATE_PARAMETERS is defined.

Use of const_mem_fun_explicit and mem_fun_explicit

MSVC++ 6.0 has problems with const member functions as non-type template parameters, and thus does not accept the const_mem_fun key extractor. A simple workaround, fortunately, has been found, consisting in specifying the type of these pointers as an additional template parameter. The alternative const_mem_fun_explicit extractor adopts this solution; for instance, given the type

struct A
{
  int f()const;
};

the extractor const_mem_fun<A,int,&A::f> can be replaced by const_mem_fun_explicit<A,int,int (A::*)()const,&A::f>. A similar mem_fun_explicit class template is provided for non-constant member functions.

If you are writing cross-platform code, the selection of either key extractor is transparently handled by the macro BOOST_MULTI_INDEX_CONST_MEM_FUN, so that

BOOST_MULTI_INDEX_CONST_MEM_FUN(A,int,f)

expands by default to

const_mem_fun<A,int,&A::f>

but resolves to

const_mem_fun_explicit<A,int,int (A::*)()const,&A::f>

in MSVC++ 6.0. Non-const member functions are covered by mem_fun_explicit and the macro BOOST_MULTI_INDEX_MEM_FUN.

composite_key in compilers without partial template specialization

When using composite_keys, lookup is performed by passing tuples of values: this ability is achieved by suitably specializing the class templates std::equal_to, std::less, std::greater and boost::hash for composite_key_result instantiations so that they provide the appropriate overloads accepting tuples --and in the case of std::less and std::greater, also partial tuples where only the first components are specified.

In those compilers that do not support partial template specialization, these specializations cannot be provided, and so tuple-based lookup is not available by default. In this case, multi_index_container instantiations using composite keys will work as expected, both for ordered and hashed indices, except that lookup operations will not accept tuples as an argument. For ordered indices, the most obvious workaround to this deficiency involves explicitly specifying the comparison predicate with composite_key_compare; in the case of hashed indices we can use the analogous composite_key_equal_to and composite_key_hash. This substitution is tedious as the elementary components for all the constituent key extractors must be explicitly typed. For this reason, Boost.MultiIndex provides the following replacement class templates

that act as the missing specializations of std::equal_to, std::less, std::greater and boost::hash for composite_key_results. They can be used as follows:

typedef composite_key<
  phonebook_entry,
  member<phonebook_entry,std::string,&phonebook_entry::family_name>,
  member<phonebook_entry,std::string,&phonebook_entry::given_name>
> ckey_t;

typedef multi_index_container<
  phonebook_entry,
  indexed_by<
    ordered_non_unique< 
      ckey_t,
      // composite_key_result_less plays the role of
      // std::less<ckey_t::result_type>
      composite_key_result_less<ckey_t::result_type>
    >,
    ordered_unique<
      member<phonebook_entry,std::string,&phonebook_entry::phone_number>
    >
  >
> phonebook;

Reduction of symbol name lengths

The types generated on the instantiations of multi_index_containers typically produce very long symbol names, sometimes beyond the internal limits of some compilers. There are several techniques to shorten generated symbol names: these techniques have also the beneficial side effect that resulting error messages are more readable.

Limitation of maximum number of arguments

The class templates indexed_by, tag and composite_key accept a variable number of arguments whose maximum number is limited by internal macros. Even non-used arguments contribute to the final types, so manually adjusting the corresponding macros can result in a modest reduction of symbol names.

Limiting maximum number of arguments of some class templates of Boost.MultiIndex.
class template limiting macro default value default value
(MSVC++ 6.0)
 indexed_by   BOOST_MULTI_INDEX_LIMIT_INDEXED_BY_SIZE  20 5
 tag   BOOST_MULTI_INDEX_LIMIT_TAG_SIZE  20 3
 composite_key   BOOST_MULTI_INDEX_LIMIT_COMPOSITE_KEY_SIZE  10 5

Type hiding

Consider a typical instantiation of multi_index_container:

typedef multi_index_container<
  employee,
  indexed_by<
    ordered_unique<identity<employee> >,
    ordered_non_unique<member<employee,std::string,&employee::name> >,
    ordered_unique<member<employee,int,&employee::ssnumber> >
  >
> employee_set;

Then, for instance, the type employee_set::nth_index<0>::type resolves to the following in GCC:

boost::multi_index::detail::ordered_index<
  boost::multi_index::identity<employee>,
  std::less<employee>,
  boost::multi_index::detail::nth_layer<
    1, employee,
    boost::multi_index::indexed_by<
      boost::multi_index::ordered_unique<
        boost::multi_index::identity<employee>, mpl_::na, mpl_::na
      >,
      boost::multi_index::ordered_non_unique<
        boost::multi_index::member<employee, std::string, &employee::name>,
        mpl_::na, mpl_::na
      >,
      boost::multi_index::ordered_unique<
        boost::multi_index::member<employee, int, &employee::ssnumber>,
        mpl_::na, mpl_::na
      >,
      mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na,
      mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na,
      mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na
    >,
    std::allocator<employee>
  >,
  boost::mpl::vector0<mpl_::na>,
  boost::multi_index::detail::ordered_unique_tag
>

It can be seen that a significant portion of the type name is contributed by the indexed_by<...> part, which is nothing but an expanded version of the index specifier list provided in the definition of employee_set. We can prevent this very long name from appearing in the final type by encapsulating it into another, shorter-named construct:

// reducing symbol names through type hiding
// type hide the index spexifier list within employee_set_indices

struct employee_set_indices:
  indexed_by<
    ordered_unique<identity<employee> >,
    ordered_non_unique<member<employee,std::string,&employee::name> >,
    ordered_unique<member<employee,int,&employee::ssnumber> >
  >
{};

typedef multi_index_container<
  employee,
  employee_set_indices
> employee_set;

employee_set_indices works as a conventional typedef in all respects, save for a detail: its name does not explicitly include the information contained in the indexed_by instantiation. Applying this technique, employee_set::nth_index<0>::type now becomes:

boost::multi_index::detail::ordered_index<
  boost::multi_index::identity<employee>,
  std::less<employee>,
  boost::multi_index::detail::nth_layer<
    1, employee,
    employee_set_indices,
    std::allocator<employee>
  >,
  boost::mpl::vector0<mpl_::na>,
  boost::multi_index::detail::ordered_unique_tag
>

which is considerably shorter than the original, and also more easily parsed by a human reader. Type hiding would not work if, instead of making employee_set_indices a derived struct of indexed_by<...>, we had defined it as a typedef: typedefs are syntactic aliases and usually get expanded by the compiler before doing any further type handling.

Type hiding techniques can also be applied to composite_key intantiations, which often contribute a great deal to symbol name lengths.




Revised March 31st 2009

© Copyright 2003-2009 Joaquín M López Muñoz. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)