Compiler Warning 552 with bitset

[Craig Chariton <ch...@roguewave.com>]

I am getting a compiler Warning 552 on HP-UX 11.11 with an A.03.63
compiler.  Here is the code that recreates the warning:

 

#include <bitset>

#include <iostream>

#include <string>

#include <cstring>

 

int main(void)

{

            const char *a = "11";

            std::bitset<8> header(static_cast<std::string>(a));

            for (std::string::size_type i =0; i < header.size();++i)

            {

                        std::cout << header[i] << "\n";                 

            }

        std::cout << header.to_string<char, std::char_traits<char>, 

               std::allocator<char> >() + "" 

               << std::endl; 

        return 0;

}

 

I am not seeing this with gcc on Linux.  The code appears to run the
fine on in both cases.  I was just wondering if this is a compiler issue
and, if so, is there any reason for concern?

 

Craig Chariton

 

Re: Compiler Warning 552 with bitset

[Martin Sebor <se...@roguewave.com>]

Craig Chariton wrote:
> I am getting a compiler Warning 552 on HP-UX 11.11 with an A.03.63
> compiler.  Here is the code that recreates the warning:
> 
[...]
> I am not seeing this with gcc on Linux.  The code appears to run the
> fine on in both cases.  I was just wondering if this is a compiler issue
> and, if so, is there any reason for concern?


The answers are yes and no.

The HP bug number is JAGaf00255. The details of the bug report
are here: http://bugzilla.cvo.roguewave.com/show_bug.cgi?id=1536

There is no reason for concern, the compiler does the right thing
despite the warning. The warning can be suppressed either via the
compiler option +W552 or by #defining the configuration macro
_RWSTD_NO_EXT_BITSET_TO_STRING and disabling the library feature
that is giving the compiler trouble.

Note that since stdcxx implements the resolution of issue 434
and also provides, as a conforming extension, an overloaded
bitset ctor that takes a const char* argument, the program can
be simplified like this:

#include <bitset>
#include <iostream>

int main ()
{
     const char *a = "11";

     const std::bitset<8> header(a);   // stdcxx extension

     for (std::string::size_type i = 0; i < header.size (); ++i) {
         std::cout << header [i] << "\n";
     }

     std::cout << header.to_string () << '\n';   // issue 434
}

Here's issue 434:
http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#434