Re: Good idea or gimmick: Go-style OO-programming in C++ ?

From:
=?ISO-8859-1?Q?=D6=F6_Tiib?= <ootiib@hot.ee>
Newsgroups:
comp.lang.c++
Date:
Sun, 10 Mar 2013 22:44:48 -0700 (PDT)
Message-ID:
<46d5473f-8490-4ec2-aa15-5338dd3f0336@googlegroups.com>
On Monday, 11 March 2013 04:26:50 UTC+2, woodb...@gmail.com wrote:

I will report one thing.

#if 0
  char* CstringGive ()
  {
    ::cmw::marshalling_integer slen(*this);
    char* cstr = ::new char[slen.value + 1];
    try {
      Give(cstr, slen.value);
      *(cstr + slen.value) = '\0';
    } catch (...) {
      ::delete [] cstr;
      throw;
    }
    return cstr;
  }

#else

  char* CstringGive ()


Error! I see 'char*' my rules suggested against raw pointers. ;)

  {

    ::cmw::marshalling_integer slen(*this);

    ::std::unique_ptr<char[]> cstr(::new char[slen.value + 1]);


You should not use smart pointers for dynamic arrays. Use std::vector
or std::string. Smart pointer does 'delete', not 'delete[]' and so
you result with undefined behavior.

    Give(cstr.get(), slen.value);
    *(cstr.get() + slen.value) = '\0';
    return cstr.get();
  }
#endif

An executable produced by g++ 4.7.2 with -Os is 32 bytes
larger using the second version than the first. Maybe it's
a weakness of this compiler? :)


Some bytes here or there. I was suggesting that RAII is better
versus GC. Stefan Ram asked how to avoid leaks, I suggested
robust rules for applying RAII. I did not say that it is
cost-free in all situations. 'char*' usually loses even to
'std::string' in performance. Vital length information is
missing in 'char*'. That is important for most operations
with strings and so algorithms have to search for terminator
'\0' with it.
 

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