how can I call the function wglSwapIntervalEXT

i want to use it, to disable vsync.

in wglext.h its defined as:

extern BOOL WINAPI wglSwapIntervalEXT (int interval);
extern int WINAPI wglGetSwapIntervalEXT (void);

When I try to compile the program, I get:

'wglSwapIntervalEXT': identifier not found

You have to load a pointer to this function using wglGetProcAddress while the context is current. You may then call the pointer returned by this function.