add finalizer to SCIPModel

Author: rschwarz

src/types.jl

@@ -13,11 +13,18 @@ type SCIPModel
         # TODO: check return code (everywhere!)
         ccall((:CSIPcreateModel, libcsip), Cint, (Ptr{Ptr{Void}}, ), _arr)
         m = new(_arr[1], options)
-        # QUESTION: Why is _arr not garbage-collected?
+        @assert m.ptr_model != C_NULL
+
+        finalizer(m, freescip)
         return m
     end
 end
 
+function freescip(m::SCIPModel)
+    @assert m.ptr_model != C_NULL
+    _freeModel(m)
+end
+
 # Linear Quadratic Model
 
 type SCIPLinearQuadraticModel <: AbstractLinearQuadraticModel

src/wrapper.jl

@@ -10,8 +10,8 @@ function _patchVersion()
     ccall((:CSIPpatchVersion, libcsip), Cint, ())
 end
 
-function _freeModel(model::SCIPMathProgModel)
-    ccall((:CSIPfreeModel, libcsip), Cint, (Ptr{Void}, ), model.inner.ptr_model)
+function _freeModel(inner::SCIPModel)
+    ccall((:CSIPfreeModel, libcsip), Cint, (Ptr{Void}, ), inner.ptr_model)
 end
 
 function _addVar(model::SCIPMathProgModel, lowerbound::Cdouble,