id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
11029,"Overloading ambiguity between basic_string & insert(0,...) and iterator insert(0,...)",sergey.sprogis@…,John Maddock,"1. Description of the failure

Let's consider the following 7 line t.cc test:


#include <string>

#include <iostream>

int main() {

 std::string s;

 s.insert(0, 1, '1');

 std::cout << s << std::endl;

}

Its complation on Solaris 11.2 with Oracle Studio 12.4 C++ compiler using -library=stlport4  option
(which tells compiler to use STL Standard library) produces the following error messages


""l.cc"", line 6: Error: Overloading ambiguity between

""std::string::insert(char*, unsigned, char)"" and

""std::string::insert(unsigned, unsigned, char)"".

The similar code containing

  <id>.insert(0,<integer>,'<character>');

exist in the following 7 headers of multiprecision library:


 multiprecision/tommath.hpp,
 multiprecision/cpp_dec_float.hpp,
 multiprecision/cpp_bin_float/io.hpp,
 multiprecision/cpp_int.hpp,
 multiprecision/number.hpp,
 multiprecision/detail/number_base.hpp,
 multiprecision/detail/float_string_cvt.hpp


which is the reason for numerous compilation failures in regression unit  tests of
multiprecision library  when any of 3 Standard librarries (Apache, STL, RW) are used 
with Studio 12.4 C++ compiler.

 2. Cause of the failure.

This failure is a direct consequence of STL implementation detail for string iterators.
C++ standard requires STL to provide the following string::insert member functions:  
                            
  basic_string& insert(size_type pos, size_type n, charT c);

  iterator insert(const_iterator p, size_type n, charT c);

Unfortunately, iterator for strings in stlport4 is implemented as 'char *' and that causes
the following call to match both of these insert functions:    
                                                        
   insert(0, 1, '1');

That happens because 0 is a valid value both for 'size_type' and 'iterator'.
And that naturally leads to the compilation failure shown above.

So its not a compiler problem but rather incompatibility between Boost sources and these STLs.

  3. Possible Solution.

To replace all lines:

<id>.insert(0,<integer>,'<character>');

with:

<id>.insert(std::string::size_type(0)<integer>,'<character>');

in 7 boost header files listed above.",Bugs,closed,To Be Determined,multiprecision,Boost 1.57.0,Problem,fixed,,