problem with using of glCopyTexImage2D.

I try to use the glCopyTexImage2D in cpp (with a GeForce2go, detonator 23.11) but my texture wasn’t filled with the framebuffer.

i made this :
(init my_current_texture with white color)

(rendering a view of my scene)
glBindTexture(my_current_texture);
glCopyTexImage2D(GL_TEXTURE_2D,0,GL_RGB,0,0,sizex,sizey,0);

(changing camera view)
(display another view of my scene with my_current_texture)
##error my_current_texture was filled in black !

I also use glCopyTexSubImage2D (more speed on nvidia card) but with the same result.

Should I pay attention to SwapBuffers order?

I didn’t found some example on the web.
Does anybody have a sample of code or idea ?

thanks!