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cgetch

Compiler gives - warning C4013: 'getche' undefined; assuming extern returning int

I'm using Visual studio for my code development and when I used the function

getche()

The compiler gave me this warning 

 warning C4013: 'getche' undefined; assuming extern returning int

But the getche() function is working just as expected , why compiler is showing such a warning , and How can I eliminate this warning?

Solution

  • As your compiler is telling you, getche has not been defined.

    Usually, you would include a header (e.g. #include <conio.h>) that will define the function somewhat similar to:

    int getche(void);

    There is a rule for the C language that allows usage of functions which have not been defined before. These functions are assumed to take the exact argument types they are passed (none, so void) and return int. Due to this feature (which is evil™) and the fact that getche does indeed get linked in due to your linker settings, your program actually works correctly.

    Be aware that getche is deprecated and you should use _getche instead.