how can i compile both c and c++ library

i have successfully created a file opencv.lib that contain a opencv libraries
and i add it to my project but when i compile it the compiler show many errors comes from cv.h
the problem that in first time when i compiled just opencv libraries there is no errors in cv.h
seemingly in my project keil consider cv.h as C code not C++
is there a method to impose keil to compile cv.h as C++ code ?

thanks for helping me :)

Build errors :

<img src="">s27.postimg.org/.../image.jpg">

main.h :

<img src="">s27.postimg.org/.../image.jpg">

main.c :

<img src="">s27.postimg.org/.../image.jpg">

i have successfully created a file opencv.lib that contain a opencv libraries
and i add it to my project but when i compile it the compiler show many errors comes from cv.h
the problem that in first time when i compiled just opencv libraries there is no errors in cv.h
seemingly in my project keil consider cv.h as C code not C++
is there a method to impose keil to compile cv.h as C++ code ?

thanks for helping me :)

Build errors :

<img src="">s27.postimg.org/.../image.jpg">

main.h :

<img src="">s27.postimg.org/.../image.jpg">

main.c :

<img src="">s27.postimg.org/.../image.jpg">

anyone can help me ?