opengl extension

[wwwwww]

Hi All:
I have some questions about the opengl extensions.
There are many header files related with opengl extensions,
glext.h, wglext.h, glew.h, and wglew.h
what is the difference between them?

Also, glew32.lib is often used with opengl extension. However,
one can still use opengl extension without any extra library.
For example, in microsoft windows platform, wglGetProcAddress could be called to get the opengl extension function. Then why do we still care about the glew32.lib?

Thanks.

[Zengar]

glext -- opengl extensions
wglext -- wgl extensions

glew -- an automated extension loading libraries for C programmers who are uncomfortable around dynamic function loading. Who cares about glew? I surely don't. I always used my own extension loading routines. But there are people who find glew more comfortable. I don't really understand what that "still" does in your question, "wglGetProcAddress" existed far longer then glew, the last one was created because lots of people found manual loading inconvenient.