Hello , all i made a decision I'd like to thank you for your help. Please, forgive me, if its not your favorite choice. It is hard to make everyone happy. So, here the winner: readPixels_x: "in" x y: "in" y width: "in" width height: "in" height format: "in" format type: "in" type pixels: "out" pixels "This method was automatically generated from OpenGL specs" "See http://squeaksource.com/OpenGLSpecs for details" <primitive: #primitiveNativeCall module: #NativeBoostPlugin> ^ self glApiCall: #( void glReadPixels ( GLint x , GLint y , GLsizei width , GLsizei height , GLenum format , GLenum type , GLvoid* pixels ) ) index: 1334 attributes: #( #category #'VERSION_1_0' #version #'1.0' ) For 1-arg: arrayElement: "in" i "This method was automatically generated from OpenGL specs" "See http://squeaksource.com/OpenGLSpecs for details" <primitive: #primitiveNativeCall module: #NativeBoostPlugin> ^ self glApiCall: #( void glArrayElement ( long i ) ) index: 15 attributes: #( #category #'VERSION_1_1_DEPRECATED' #deprecated #'3.1' #version #'1.1' ) -- Best regards, Igor Stasenko AKA sig.