Fix empty ca result handling pt2

Change-Id: I5062612ac8b4285d5fa31d24dfde2f0e81ba8704
diff --git a/Project.toml b/Project.toml
index 1c5f287..9a7e1f5 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "DerekoVecs"
 uuid = "d522d5f0-9ae6-4a1c-b144-42ce9f15cae4"
 authors = ["Marc Kupietz"]
-version = "0.4.1"
+version = "0.4.2"
 
 [deps]
 ArtifactUtils = "8b73e784-e7d8-4ea5-973d-377fed4e3bce"
diff --git a/src/DerekoVecs.jl b/src/DerekoVecs.jl
index e9da4ca..66100a8 100644
--- a/src/DerekoVecs.jl
+++ b/src/DerekoVecs.jl
@@ -193,7 +193,7 @@
 
 function get_collocates(cdb::Ptr{Nothing}, node::Int64)::Vector{collocate}
     res = @ccall libcdb.get_collocators(cdb::Ptr{collocate}, node::Cuint)::Ptr{collocate}
-    if res == 0
+    if res == Ptr{collocate}(C_NULL)
         return Vector{collocate}()
     end