<div dir="ltr">Thanks a lot!  I got , the definition is in compiler <br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">JF Bastien <<a href="mailto:jfbastien@apple.com">jfbastien@apple.com</a>> 于2019年1月24日周四 上午1:21写道：<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div style="overflow-wrap: break-word;">It’s a compiler builtin, implemented here: <a href="https://github.com/llvm/llvm-project/blob/2946cd701067404b99c39fb29dc9c74bd7193eb3/clang/lib/Sema/SemaExprCXX.cpp#L4913" target="_blank">https://github.com/llvm/llvm-project/blob/2946cd701067404b99c39fb29dc9c74bd7193eb3/clang/lib/Sema/SemaExprCXX.cpp#L4913</a><div><br><div><br><blockquote type="cite"><div>On Jan 23, 2019, at 1:18 AM, 李苏旺 via libcxx-dev <<a href="mailto:libcxx-dev@lists.llvm.org" target="_blank">libcxx-dev@lists.llvm.org</a>> wrote:</div><br class="gmail-m_8253899640733380562Apple-interchange-newline"><div><div dir="ltr"><span style="color:rgb(215,58,73);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;font-size:12px;white-space:pre-wrap">hi  man , 
   
     With all due respect I saw you have ever committed some code to LLVM project)(</span><a href="https://github.com/llvm-mirror/libcxx/blob/master/include/type_traits" style="font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;font-size:12px;white-space:pre-wrap" target="_blank">https://github.com/llvm-mirror/libcxx/blob/master/include/type_traits</a><span style="color:rgb(215,58,73);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;font-size:12px;white-space:pre-wrap">) , I am reading the source code about meta-programming in the file - type_traits
in the line number 3445 , "__is_trivially_constructible<</span><span style="color:rgb(215,58,73);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;font-size:12px;white-space:pre-wrap">...>" is curious to me , but I can not find the definition of the value , could you
please tell where I can find the definition about 

__is_trivially_constructible

?

template <class _Tp, class... _Args>
struct _LIBCPP_TEMPLATE_VIS is_trivially_constructible
    : integral_constant<bool, __is_trivially_constructible(_</span><span style="color:rgb(215,58,73);font-family:SFMono-Regular,Consolas,"Liberation Mono",Menlo,Courier,monospace;font-size:12px;white-space:pre-wrap">Tp, _Args...)>
{
};

similarly,  if I can understand the meaning of "__is_trivially_constructible" , I can understand __is_trivial ,__is_trivially_copyable , etc

thank you in advance . 
</span><br class="gmail-m_8253899640733380562gmail-Apple-interchange-newline"></div>
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