OpenGL man pages
gluNurbsCallback - define a callback for a NURBS object
void gluNurbsCallback( GLUnurbsObj *nobj,
void (*fn)( )
nobj Specifies the NURBS object (created with gluNewNurbsRenderer).
which Specifies the callback being defined. The only valid value is
fn Specifies the function that the callback calls.
gluNurbsCallback is used to define a callback to be used by a NURBS object.
If the specified callback is already defined, then it is replaced. If fn
is NULL, then any existing callback is erased.
The one legal callback is GLU_ERROR:
GLU_ERROR The error function is called when an error is encountered.
Its single argument is of type GLenum, and it indicates the
specific error that occurred. There are 37 errors unique to
NURBS named GLU_NURBS_ERROR1 through GLU_NURBS_ERROR37.
Character strings describing these errors can be retrieved
Fri Dec 6 11:18:03 EST 1996
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