getch returns 2 characters when I type one





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4















When I use getch, it always appends the caracter read with a null character.



When I use the following code:



#include "stdafx.h"

#include <conio.h>



int main()

{

    char c = 0;



    while (c != 'x')

    {

        c = _getch();

        printf("Char read: <%c> n", c);

    }

}


It returns the follwing on the console, when I press the keys "asdx":



Char read: <a>

Char read: < >

Char read: <s>

Char read: < >

Char read: <d>

Char read: < >

Char read: <x>


This is compiled in VS 2017 in a plain new single file project, running on a windows 10 console window. I tried removing the _UNICODE and UNICODE define.






c++ visual-studio-2017 console-application







share|improve this question























  • How do you know it's a null character? BTW _getch() returns int.

    – n.m.
    Aug 10 '18 at 18:48








  • 2





    works as expected for me, have you tried printing the numerical value of c to see what it is?

    – Alan Birtles
    Aug 10 '18 at 18:48











  • I know it's a null because I traced it into the debugger. I tried with either int or char, I got the same result.

    – Vincent Hubert
    Aug 10 '18 at 18:52






  • 1





    This is apparently a problem in some versions of Windows SDK, see developercommunity.visualstudio.com/content/problem/247770/…

    – n.m.
    Aug 10 '18 at 18:55








  • 1





    @AlanBirtles: it works for me in Debug mode but fails in Release mode. Same behavior as OP.

    – Thomas Weller
    Aug 10 '18 at 18:55


















4















When I use getch, it always appends the caracter read with a null character.



When I use the following code:



#include "stdafx.h"

#include <conio.h>



int main()

{

    char c = 0;



    while (c != 'x')

    {

        c = _getch();

        printf("Char read: <%c> n", c);

    }

}


It returns the follwing on the console, when I press the keys "asdx":



Char read: <a>

Char read: < >

Char read: <s>

Char read: < >

Char read: <d>

Char read: < >

Char read: <x>


This is compiled in VS 2017 in a plain new single file project, running on a windows 10 console window. I tried removing the _UNICODE and UNICODE define.






c++ visual-studio-2017 console-application







share|improve this question























  • How do you know it's a null character? BTW _getch() returns int.

    – n.m.
    Aug 10 '18 at 18:48








  • 2





    works as expected for me, have you tried printing the numerical value of c to see what it is?

    – Alan Birtles
    Aug 10 '18 at 18:48











  • I know it's a null because I traced it into the debugger. I tried with either int or char, I got the same result.

    – Vincent Hubert
    Aug 10 '18 at 18:52






  • 1





    This is apparently a problem in some versions of Windows SDK, see developercommunity.visualstudio.com/content/problem/247770/…

    – n.m.
    Aug 10 '18 at 18:55








  • 1





    @AlanBirtles: it works for me in Debug mode but fails in Release mode. Same behavior as OP.

    – Thomas Weller
    Aug 10 '18 at 18:55














4












4








4








When I use getch, it always appends the caracter read with a null character.



When I use the following code:



#include "stdafx.h"

#include <conio.h>



int main()

{

    char c = 0;



    while (c != 'x')

    {

        c = _getch();

        printf("Char read: <%c> n", c);

    }

}


It returns the follwing on the console, when I press the keys "asdx":



Char read: <a>

Char read: < >

Char read: <s>

Char read: < >

Char read: <d>

Char read: < >

Char read: <x>


This is compiled in VS 2017 in a plain new single file project, running on a windows 10 console window. I tried removing the _UNICODE and UNICODE define.






c++ visual-studio-2017 console-application







share|improve this question














When I use getch, it always appends the caracter read with a null character.



When I use the following code:



#include "stdafx.h"

#include <conio.h>



int main()

{

    char c = 0;



    while (c != 'x')

    {

        c = _getch();

        printf("Char read: <%c> n", c);

    }

}


It returns the follwing on the console, when I press the keys "asdx":



Char read: <a>

Char read: < >

Char read: <s>

Char read: < >

Char read: <d>

Char read: < >

Char read: <x>


This is compiled in VS 2017 in a plain new single file project, running on a windows 10 console window. I tried removing the _UNICODE and UNICODE define.






c++ visual-studio-2017 console-application




c++ visual-studio-2017 console-application






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Aug 10 '18 at 18:40









Vincent HubertVincent Hubert

1,161819




1,161819













  • How do you know it's a null character? BTW _getch() returns int.

    – n.m.
    Aug 10 '18 at 18:48








  • 2





    works as expected for me, have you tried printing the numerical value of c to see what it is?

    – Alan Birtles
    Aug 10 '18 at 18:48











  • I know it's a null because I traced it into the debugger. I tried with either int or char, I got the same result.

    – Vincent Hubert
    Aug 10 '18 at 18:52






  • 1





    This is apparently a problem in some versions of Windows SDK, see developercommunity.visualstudio.com/content/problem/247770/…

    – n.m.
    Aug 10 '18 at 18:55








  • 1





    @AlanBirtles: it works for me in Debug mode but fails in Release mode. Same behavior as OP.

    – Thomas Weller
    Aug 10 '18 at 18:55



















  • How do you know it's a null character? BTW _getch() returns int.

    – n.m.
    Aug 10 '18 at 18:48








  • 2





    works as expected for me, have you tried printing the numerical value of c to see what it is?

    – Alan Birtles
    Aug 10 '18 at 18:48











  • I know it's a null because I traced it into the debugger. I tried with either int or char, I got the same result.

    – Vincent Hubert
    Aug 10 '18 at 18:52






  • 1





    This is apparently a problem in some versions of Windows SDK, see developercommunity.visualstudio.com/content/problem/247770/…

    – n.m.
    Aug 10 '18 at 18:55








  • 1





    @AlanBirtles: it works for me in Debug mode but fails in Release mode. Same behavior as OP.

    – Thomas Weller
    Aug 10 '18 at 18:55

















How do you know it's a null character? BTW _getch() returns int.

– n.m.
Aug 10 '18 at 18:48







How do you know it's a null character? BTW _getch() returns int.

– n.m.
Aug 10 '18 at 18:48






2




2





works as expected for me, have you tried printing the numerical value of c to see what it is?

– Alan Birtles
Aug 10 '18 at 18:48





works as expected for me, have you tried printing the numerical value of c to see what it is?

– Alan Birtles
Aug 10 '18 at 18:48













I know it's a null because I traced it into the debugger. I tried with either int or char, I got the same result.

– Vincent Hubert
Aug 10 '18 at 18:52





I know it's a null because I traced it into the debugger. I tried with either int or char, I got the same result.

– Vincent Hubert
Aug 10 '18 at 18:52




1




1





This is apparently a problem in some versions of Windows SDK, see developercommunity.visualstudio.com/content/problem/247770/…

– n.m.
Aug 10 '18 at 18:55







This is apparently a problem in some versions of Windows SDK, see developercommunity.visualstudio.com/content/problem/247770/…

– n.m.
Aug 10 '18 at 18:55






1




1





@AlanBirtles: it works for me in Debug mode but fails in Release mode. Same behavior as OP.

– Thomas Weller
Aug 10 '18 at 18:55





@AlanBirtles: it works for me in Debug mode but fails in Release mode. Same behavior as OP.

– Thomas Weller
Aug 10 '18 at 18:55












2 Answers
2






active

oldest

votes


















4














Well, crap!



It's a (rather new) bug in windows.



https://developercommunity.visualstudio.com/content/problem/247770/-getch-broken-in-vs-157.html




"When building a console application using the _getch() function
suddenly returns two times for each keypress"




got the following response from microsoft:




" Thanks for reporting this! This will be fixed on a future windows
update."




UPDATE:
As stated in the link above, setting the runtime to statically link with a previous version of the C runtime will fix the issue, but you need to make sure all your related projects (if you are building a library, for example) also use the same runtime. (I tested it)






share|improve this answer

































    2














    If you don't want to (or you can't) use a previous version of the Universal C Runtime, you can use _getwch instead of _getch, as the problem doesn't affect to _getwch function.



    Note that _getwch can return Unicode characters, so it may return distinct values than _getch for some keys. For example, for € character, _getch returns 0x3f (?) while _getwch returns 0x20ac (Unicode value for €)






    share|improve this answer
























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      2 Answers
      2






      active

      oldest

      votes








      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      4














      Well, crap!



      It's a (rather new) bug in windows.



      https://developercommunity.visualstudio.com/content/problem/247770/-getch-broken-in-vs-157.html




      "When building a console application using the _getch() function
      suddenly returns two times for each keypress"




      got the following response from microsoft:




      " Thanks for reporting this! This will be fixed on a future windows
      update."




      UPDATE:
      As stated in the link above, setting the runtime to statically link with a previous version of the C runtime will fix the issue, but you need to make sure all your related projects (if you are building a library, for example) also use the same runtime. (I tested it)






      share|improve this answer






























        4














        Well, crap!



        It's a (rather new) bug in windows.



        https://developercommunity.visualstudio.com/content/problem/247770/-getch-broken-in-vs-157.html




        "When building a console application using the _getch() function
        suddenly returns two times for each keypress"




        got the following response from microsoft:




        " Thanks for reporting this! This will be fixed on a future windows
        update."




        UPDATE:
        As stated in the link above, setting the runtime to statically link with a previous version of the C runtime will fix the issue, but you need to make sure all your related projects (if you are building a library, for example) also use the same runtime. (I tested it)






        share|improve this answer




























          4












          4








          4







          Well, crap!



          It's a (rather new) bug in windows.



          https://developercommunity.visualstudio.com/content/problem/247770/-getch-broken-in-vs-157.html




          "When building a console application using the _getch() function
          suddenly returns two times for each keypress"




          got the following response from microsoft:




          " Thanks for reporting this! This will be fixed on a future windows
          update."




          UPDATE:
          As stated in the link above, setting the runtime to statically link with a previous version of the C runtime will fix the issue, but you need to make sure all your related projects (if you are building a library, for example) also use the same runtime. (I tested it)






          share|improve this answer















          Well, crap!



          It's a (rather new) bug in windows.



          https://developercommunity.visualstudio.com/content/problem/247770/-getch-broken-in-vs-157.html




          "When building a console application using the _getch() function
          suddenly returns two times for each keypress"




          got the following response from microsoft:




          " Thanks for reporting this! This will be fixed on a future windows
          update."




          UPDATE:
          As stated in the link above, setting the runtime to statically link with a previous version of the C runtime will fix the issue, but you need to make sure all your related projects (if you are building a library, for example) also use the same runtime. (I tested it)







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Aug 10 '18 at 19:29

























          answered Aug 10 '18 at 18:56









          Vincent HubertVincent Hubert

          1,161819




          1,161819

























              2














              If you don't want to (or you can't) use a previous version of the Universal C Runtime, you can use _getwch instead of _getch, as the problem doesn't affect to _getwch function.



              Note that _getwch can return Unicode characters, so it may return distinct values than _getch for some keys. For example, for € character, _getch returns 0x3f (?) while _getwch returns 0x20ac (Unicode value for €)






              share|improve this answer




























                2














                If you don't want to (or you can't) use a previous version of the Universal C Runtime, you can use _getwch instead of _getch, as the problem doesn't affect to _getwch function.



                Note that _getwch can return Unicode characters, so it may return distinct values than _getch for some keys. For example, for € character, _getch returns 0x3f (?) while _getwch returns 0x20ac (Unicode value for €)






                share|improve this answer


























                  2












                  2








                  2







                  If you don't want to (or you can't) use a previous version of the Universal C Runtime, you can use _getwch instead of _getch, as the problem doesn't affect to _getwch function.



                  Note that _getwch can return Unicode characters, so it may return distinct values than _getch for some keys. For example, for € character, _getch returns 0x3f (?) while _getwch returns 0x20ac (Unicode value for €)






                  share|improve this answer













                  If you don't want to (or you can't) use a previous version of the Universal C Runtime, you can use _getwch instead of _getch, as the problem doesn't affect to _getwch function.



                  Note that _getwch can return Unicode characters, so it may return distinct values than _getch for some keys. For example, for € character, _getch returns 0x3f (?) while _getwch returns 0x20ac (Unicode value for €)







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Oct 30 '18 at 12:53









                  gusitoguaygusitoguay

                  1106




                  1106






























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