error: 'string_view' is not a member of 'std'

Question

i am new to c++. i compiled my code in visual-studio-code in windows10, with 2 variables of type string and string_view. string variable is fine, but string_view is giving errors.I also enable c++17 extension in configuration.json and edit configuration/ui file in vscode.

Here is my code:=

#include<iostream>
#include<string_view>
using namespace std;
int main(){
      string str="hello";
      cout<<str<<endl;
      std::string_view sv=" world";
      auto result=str+sv.data();

      return 0;
}

errors are:=

main.cpp: In function 'int main()':
main.cpp:7:12: error: 'string_view' is not a member of 'std'
       std::string_view sv=" world";
            ^~~~~~~~~~~
main.cpp:7:12: note: 'std::string_view' is only available from C++17 onwards
main.cpp:8:23: error: 'sv' was not declared in this scope
       auto result=str+sv.data();
                       ^~

What compiler are you using? visual studio code is a text editor. It is not an IDE for compiling and building. — R Sahu, Oct 04 '19 at 04:34

Saurav Rai · Accepted Answer · 2019-10-04T05:23:19.857

17

I didn't find any bug in your code. I compiled your code here (Copy your code there and select the language C++17 before compiling) and it is working as expected. Just check the compiler which you are running supports C++17 features. Because std::string_view is only available from C++17 onwards. To enable C++17 in Visual studio check here and in Visual studio code follow this .

Hope this will help you.

edited Oct 04 '19 at 05:23

answered Oct 04 '19 at 04:38

Saurav Rai

2,171
1
15
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@Abhi38 I have given you the link in the answer above. Kindly look into it. Thanks – Saurav Rai Oct 04 '19 at 05:10
thanks for reply. But, I am using visual-studio-code NOT visual studio17 – Abhi38 Oct 04 '19 at 05:16
@Abhi38: Visual Studio Code is *not* your compiler. How your code gets compiled is governed by your compiler. So that's what you need to focus on enabling which language you're compiling for. – Nicol Bolas Oct 04 '19 at 05:22
@Abhi38 I hope you got it now. Thanks – Saurav Rai Oct 04 '19 at 05:27
@Abhi38 Would you correct my answer as right. It would be very useful for others as well. Thanks. – Saurav Rai Oct 04 '19 at 06:33

score 2 · Answer 2 · answered May 01 '20 at 04:34

I'm using gcc compiler for visual studio code. In C++17, gcc has made some changed, including integrating string_view and string together. I think that it seem more complicated now,as string will implicitly convert to string_view, in some case.

For more detail:

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0254r2.pdf

score 2 · Answer 3 · answered May 05 '21 at 04:57

2

i solved this error by going to .. project > properties ... select all configurations... > Configuration Properties > C/C++ > Language > C++ Language Standard > ...select ISO C++ 17 Standard(/std::c++17)enter image description here

answered May 05 '21 at 04:57

elizandrold

31
3

score 0 · Answer 4 · answered Nov 27 '20 at 21:09

By default, VS sets up the project to x86, but when you open properties, it loads x64 instead. I think VS should load the same settings you are currently using in the IDE, but that's just a personal opinion.

Setting C++17 standard for x86 solved to problem for me. This solution worked for me https://developercommunity.visualstudio.com/content/problem/1133349/namespace-std-has-no-member-string-view.html

error: 'string_view' is not a member of 'std'

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