Question

我无法弄清楚如何在recursive_directory_iterator上使用Concurrency :: parallel_for，编译器不喜欢Step param。

你可以将parallel_for [each]东西用于除数组以外的任何东西吗？

简单代码：

    recursive_directory_iterator dir(cwd, directory_options::skip_permission_denied);
    recursive_directory_iterator end_dir;

    parallel_for(begin(dir), end(dir), begin(dir), [&](recursive_directory_iterator dir) {

    });

导致关于第三个参数_Step：

的大量错误

Error   C2678   binary '<': no operator found which takes a left-hand operand of type 'std::filesystem::recursive_directory_iterator' (or there is no acceptable conversion)    app c:\program files (x86)\microsoft visual studio\2017\enterprise\vc\tools\msvc\14.14.26428\include\ppl.h  2501    
Error   C2678   binary '>=': no operator found which takes a left-hand operand of type 'std::filesystem::recursive_directory_iterator' (or there is no acceptable conversion)   app c:\program files (x86)\microsoft visual studio\2017\enterprise\vc\tools\msvc\14.14.26428\include\ppl.h  2507    
Error   C2784   'unknown-type std::operator -(const std::move_iterator<_RanIt> &,const std::move_iterator<_RanIt2> &)': could not deduce template argument for 'const std::move_iterator<_RanIt> &' from 'std::filesystem::recursive_directory_iterator'    app c:\program files (x86)\microsoft visual studio\2017\enterprise\vc\tools\msvc\14.14.26428\include\ppl.h  2514    
Error   C2784   'unknown-type std::operator -(const std::reverse_iterator<_RanIt> &,const std::reverse_iterator<_RanIt2> &)': could not deduce template argument for 'const std::reverse_iterator<_RanIt> &' from 'std::filesystem::recursive_directory_iterator'   app c:\program files (x86)\microsoft visual studio\2017\enterprise\vc\tools\msvc\14.14.26428\include\ppl.h  2514    
Error   C2676   binary '-': 'std::filesystem::recursive_directory_iterator' does not define this operator or a conversion to a type acceptable to the predefined operator   app c:\program files (x86)\microsoft visual studio\2017\enterprise\vc\tools\msvc\14.14.26428\include\ppl.h  2514    
Error   C2672   '_Parallel_for_partitioned_impl': no matching overloaded function found app c:\program files (x86)\microsoft visual studio\2017\enterprise\vc\tools\msvc\14.14.26428\include\ppl.h  2525    
Error   C2893   Failed to specialize function template 'void Concurrency::_Parallel_for_partitioned_impl(_Index_type,_Diff_type,_Diff_type,const _Function &,const Concurrency::auto_partitioner &)'    app c:\program files (x86)\microsoft visual studio\2017\enterprise\vc\tools\msvc\14.14.26428\include\ppl.h  2525

看起来我需要以某种方式调整迭代器，但我不确定如何 - 我可以将dir recurse转换为数组，但这感觉不太正确。

有什么想法吗？

TIA

如何在recursive_directory_iterator上使用parallel_for？

0 个答案: