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POC++ library API. Using converter classes instead of plain C api
 

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  1. POC++ library API. Using converter classes instead of plain C api
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    <p>This question is about C++ &lt;-> C++ interoperability.</p> <p>As is well known implementation of standard library classes/functions may differ across different vendors. Moreover implementation may differ even within same library vendor, when using different compiler keys, configuration (Debug/Release), etc.</p> <p>Due to that reason, many library developers shifts to old plain C-style API. Which leads to uglish error-prone interfaces.</p> <p>For instance, in order to get string from some function, interfaces like Win GetCurrentDirectory function are used:</p> <pre><code>DWORD WINAPI GetCurrentDirectory( __in DWORD nBufferLength, __out LPTSTR lpBuffer ); </code></pre> <p>three parameters + some boilerplate code on both sides(checking if buffer size was enough, etc) just to get simple string.</p> <p>I am thinking to use some auxiliary adapter/proxy class, which will do all conversions automaticly, and can be simply reused.</p> <p>Something like:</p> <pre><code>#include &lt;string&gt; #include &lt;algorithm&gt; #include &lt;iostream&gt; #include &lt;ostream&gt; class StringConverter { char *str; // TODO: use smart pointer with right deleter public: StringConverter(const std::string &amp;user_string) // Will be defined only at user side { str=new char[user_string.length()+1]; (*(std::copy(user_string.begin(),user_string.end(),str)))=0; } operator std::string() // Will be defined only at library side { return std::string(str); } ~StringConverter() { delete [] str; } }; StringConverter foo() { return std::string("asd"); } int main(int argc,char *argv[]) { std::cout &lt;&lt; std::string(foo()) &lt;&lt; std::endl; return 0; } </code></pre> <p><a href="http://ideone.com/EfcKv" rel="nofollow">http://ideone.com/EfcKv</a></p> <p>Note, I plan to have defenition of conversion from user string to StringConverter only at user side, and defenition of conversion from StringConverter to library string only inside library. Also, right deleter should be used (from right heap).</p> <p>What do you think about such approach?</p> <p>Are there some major pitfalls?</p> <p>Are there some superior alternatives?</p>
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    1. COYour code violates the rule of three, and has no apparent purpose. Please show an example.
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      1. USCheers and hth. - Alf
    2. CO"violates the rule of three" - yes, I know, it is just for demonstration.
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    3. CO"no apparent purpose", reread my question, see where conversions are defined. Hint: different std::string implementations
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