   Undefined References
  I downloaded the source file for dev-c++ (my version is 4.01) and I'm getting the following errors:C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x38):lesson1.cpp: undefined reference to `glViewport@16'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x45):lesson1.cpp: undefined reference to `glMatrixMode@4'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x4d):lesson1.cpp: undefined reference to `glLoadIdentity@0'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x84):lesson1.cpp: undefined reference to `gluPerspective@32'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x91):lesson1.cpp: undefined reference to `glMatrixMode@4'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x99):lesson1.cpp: undefined reference to `glLoadIdentity@0'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0xb7):lesson1.cpp: undefined reference to `glShadeModel@4'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0xd1):lesson1.cpp: undefined reference to `glClearColor@16'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0xe0):lesson1.cpp: undefined reference to `glClearDepth@8'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0xf0):lesson1.cpp: undefined reference to `glEnable@4'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x100):lesson1.cpp: undefined reference to `glDepthFunc@4'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x115):lesson1.cpp: undefined reference to `glHint@8'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x13b):lesson1.cpp: undefined reference to `glClear@4'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x143):lesson1.cpp: undefined reference to `glLoadIdentity@0'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x258):lesson1.cpp: undefined reference to `wglMakeCurrent@8'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x282):lesson1.cpp: undefined reference to `wglDeleteContext@4'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x854):lesson1.cpp: undefined reference to `ChoosePixelFormat@8'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x898):lesson1.cpp: undefined reference to `SetPixelFormat@12'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x8ce):lesson1.cpp: undefined reference to `wglCreateContext@4'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0x914):lesson1.cpp: undefined reference to `wglMakeCurrent@8'C:\WINDOWS\TEMP\cchgEYfb.o(.text+0xc2f):lesson1.cpp: undefined reference to `SwapBuffers@4'why is that happenning?    
  add the OpenGl library to your link step.   ;  Well, i linked the files and now i'm getting this:C:\DEV-C_~1\BIN\ld.exe: C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll): warning: ignoring duplicate section `.text'C:\DEV-C_~1\BIN\ld.exe: C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll): warning: ignoring duplicate section `.idata$5'C:\DEV-C_~1\BIN\ld.exe: C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll): warning: ignoring duplicate section `.text'C:\DEV-C_~1\BIN\ld.exe: C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll): warning: ignoring duplicate section `.idata$5'C:\DEV-C_~1\BIN\ld.exe: C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll): warning: ignoring duplicate section `.text'C:\DEV-C_~1\BIN\ld.exe: C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll): warning: ignoring duplicate section `.idata$5'C:\DEV-C_~1\BIN\ld.exe: C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll): warning: ignoring duplicate section `.text'C:\DEV-C_~1\BIN\ld.exe: C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll): warning: ignoring duplicate section `.idata$5'C:\DEV-C_~1\BIN\ld.exe: C:\Dev-C++\Lib\Glu32.lib(GLU32.dll): warning: ignoring duplicate section `.text'C:\DEV-C_~1\BIN\ld.exe: C:\Dev-C++\Lib\Glu32.lib(GLU32.dll): warning: ignoring duplicate section `.idata$5'C:\Dev-C++\Lib\Glu32.lib(GLU32.dll)(.debug$S+0x0): multiple definition of `idata$2'C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll)(.debug$S+0x0): first defined hereC:\Dev-C++\Lib\Glu32.lib(GLU32.dll)(.debug$S+0x0): multiple definition of `idata$4'C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll)(.debug$S+0x0): first defined hereC:\Dev-C++\Lib\Glu32.lib(GLU32.dll)(.debug$S+0x0): multiple definition of `idata$5'C:\Dev-C++\Lib\Opengl32.lib(OPENGL32.dll)(.debug$S+0x0): first defined here