Hello, I'm trying open-gl for the first time and I get the following error: Undefined foreign symbol: "glAttachShader" [Condition of type KERNEL:SIMPLE-PROGRAM-ERROR] Restarts: 0: [CONTINUE] Return NIL from load of #P"/home/tl/comp/lang/lisp/code/cl-opengl/gl/funcs.x86f". 1: [RETRY] Retry performing #<ASDF:LOAD-OP NIL {58E5F46D}> on #<ASDF:CL-SOURCE-FILE "funcs" {58DF96D5}>. 2: [ACCEPT] Continue, treating #<ASDF:LOAD-OP NIL {58E5F46D}> on #<ASDF:CL-SOURCE-FILE "funcs" {58DF96D5}> as having been successful. 3: [ABORT-REQUEST] Abort handling SLIME request. 4: [DESTROY] Destroy the process I am using cmucl 19c on a intel linux. I fetched cffi and cl-opengl from their respective websites today. Any advice ? Thibault Langlois --- The full session: CL-USER> (asdf:operate 'asdf:load-op 'cl-opengl) ; loading system definition from /home/tl/Projects/Systems/cl-opengl.asd ; into #<The ASDF0 package> ; Loading #P"/home/tl/comp/lang/lisp/code/cl-opengl/cl-opengl.asd". ; registering #<SYSTEM :CL-OPENGL {584F4DED}> as CL-OPENGL ; loading system definition from /home/tl/Projects/Systems/cffi.asd into ; #<The ASDF0 package> ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/cffi.asd". ; registering #<SYSTEM CFFI {5851DA7D}> as CFFI ; Compiling LAMBDA (.PV-CELL. .NEXT-METHOD-CALL. O C): ; Compiling Top-Level Form: ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/utils.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/features.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/cffi- cmucl.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/package.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/libraries.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/early- types.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/types.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/enum.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/strings.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/functions.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cffi-060626/src/foreign- vars.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cl-opengl/gl/package.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cl-opengl/gl/library.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cl-opengl/gl/types.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cl-opengl/gl/enums.x86f". ; Loading #P"/home/tl/comp/lang/lisp/code/cl-opengl/gl/funcs.x86f". ; Compilation unit aborted. ; Evaluation aborted CL-USER> (lisp-implementation-version) "19c (19C)" CL-USER> (lisp-implementation-type) "CMU Common Lisp" CL-USER> -- Thibault Langlois <tl@di.fc.ul.pt> FCUL / DI