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<p class="MsoNormal"><span style="color:#1F497D">Actually, a default move constructor is not good as it needs to swap the buffers, so I have to define it myself.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Dvir<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> llvm-dev [mailto:llvm-dev-bounces@lists.llvm.org]
<b>On Behalf Of </b>Dvir Yitzchaki via llvm-dev<br>
<b>Sent:</b> Tuesday, July 11, 2017 15:31<br>
<b>To:</b> llvm-dev@lists.llvm.org<br>
<b>Subject:</b> [llvm-dev] returning Expected<tool_output_file><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi list.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ve wrote a function which creates an output file as follows:<o:p></o:p></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:blue">llvm</span><span style="font-size:9.5pt;font-family:Consolas;color:black">::</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">Expected</span><span style="font-size:9.5pt;font-family:Consolas;color:black"><</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">llvm</span><span style="font-size:9.5pt;font-family:Consolas;color:black">::</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">tool_output_file</span><span style="font-size:9.5pt;font-family:Consolas;color:black">><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:#880000">createOutputFile</span><span style="font-size:9.5pt;font-family:Consolas;color:black">(</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">llvm</span><span style="font-size:9.5pt;font-family:Consolas;color:black">::</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">StringRef</span><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:navy">FileName</span><span style="font-size:9.5pt;font-family:Consolas;color:black">) {<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">std</span><span style="font-size:9.5pt;font-family:Consolas;color:black">::</span><i><span style="font-size:9.5pt;font-family:Consolas;color:blue">error_code</span></i><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:navy">EC</span><span style="font-size:9.5pt;font-family:Consolas;color:black">;<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">llvm</span><span style="font-size:9.5pt;font-family:Consolas;color:black">::</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">tool_output_file</span><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:navy">Out</span><span style="font-size:9.5pt;font-family:Consolas;color:black">(</span><span style="font-size:9.5pt;font-family:Consolas;color:navy">FileName</span><span style="font-size:9.5pt;font-family:Consolas;color:black">,
</span><span style="font-size:9.5pt;font-family:Consolas;color:navy">EC</span><span style="font-size:9.5pt;font-family:Consolas;color:black">,
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">llvm</span><span style="font-size:9.5pt;font-family:Consolas;color:black">::</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">sys</span><span style="font-size:9.5pt;font-family:Consolas;color:black">::</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">fs</span><span style="font-size:9.5pt;font-family:Consolas;color:black">::</span><span style="font-size:9.5pt;font-family:Consolas;color:#A000A0">F_Text</span><span style="font-size:9.5pt;font-family:Consolas;color:black">);<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">if</span><span style="font-size:9.5pt;font-family:Consolas;color:black"> (</span><span style="font-size:9.5pt;font-family:Consolas;color:navy">EC</span><span style="font-size:9.5pt;font-family:Consolas;color:black">)
{<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">return</span><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">llvm</span><span style="font-size:9.5pt;font-family:Consolas;color:black">::</span><span style="font-size:9.5pt;font-family:Consolas;color:#880000">errorCodeToError</span><span style="font-size:9.5pt;font-family:Consolas;color:black">(</span><span style="font-size:9.5pt;font-family:Consolas;color:navy">EC</span><span style="font-size:9.5pt;font-family:Consolas;color:black">);<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black"> }<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">return</span><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:navy">Out</span><span style="font-size:9.5pt;font-family:Consolas;color:black">;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.5pt;font-family:Consolas;color:black">}<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.5pt;font-family:Consolas;color:black"><o:p> </o:p></span></p>
<p class="MsoNormal">This fails to compile, however because <span style="font-size:9.5pt;font-family:Consolas;color:navy">
tool_output_file</span> is not copyable or even moveable which Expected requires.<o:p></o:p></p>
<p class="MsoNormal">If I add default move constructors to <span style="font-size:9.5pt;font-family:Consolas;color:navy">
raw_ostream</span> and <span style="font-size:9.5pt;font-family:Consolas;color:navy">
raw_fd_ostream</span> the code above compile fine.<o:p></o:p></p>
<p class="MsoNormal">Is such a patch welcome? Is there a different way to achieve this?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Regards,<o:p></o:p></p>
<p class="MsoNormal">Dvir<o:p></o:p></p>
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