diff --git a/source/adios2/core/adiosFunctions.cpp b/source/adios2/core/adiosFunctions.cpp
index 6c6901880911115bf499f3e82e1c070229cd2bfe..3394c294669a9d9e4dc927b0b0014655e6df1084 100644
--- a/source/adios2/core/adiosFunctions.cpp
+++ b/source/adios2/core/adiosFunctions.cpp
@@ -662,6 +662,16 @@ void ConvertUint64VectorToSizetVector(const std::vector<std::uint64_t> &in,
     }
 }
 
+void Uint64ArrayToSizetVector(const std::size_t nElements, const uint64_t *in,
+                              std::vector<std::size_t> &out)
+{
+    out.resize(nElements);
+    for (std::size_t i = 0; i < nElements; i++)
+    {
+        out[i] = static_cast<std::size_t>(in[i]);
+    }
+}
+
 std::vector<std::size_t> Uint64ArrayToSizetVector(const std::size_t nElements,
                                                   const uint64_t *in)
 {
diff --git a/source/adios2/core/adiosFunctions.h b/source/adios2/core/adiosFunctions.h
index 545c5c3e953b65823d0d7497d9f2cc35593758ee..a66daa87ddf5582a7e8fc41475b10d212ebf71d7 100644
--- a/source/adios2/core/adiosFunctions.h
+++ b/source/adios2/core/adiosFunctions.h
@@ -188,6 +188,13 @@ std::vector<int> CSVToVectorInt(const std::string csv);
  */
 void ConvertUint64VectorToSizetVector(const std::vector<std::uint64_t> &in,
                                       std::vector<std::size_t> &out);
+/** Convert a C array of uint64_t elements to a vector of std::size_t elements
+ *  @param number of elements
+ *  @param input array of uint64_t elements
+ *  @param vector of std::size_t elements. It will be resized to nElements.
+ */
+void Uint64ArrayToSizetVector(const std::size_t nElements, const uint64_t *in,
+                              std::vector<std::size_t> &out);
 
 /** Convert a C array of uint64_t elements to a vector of std::size_t elements
  *  @param number of elements
@@ -196,7 +203,6 @@ void ConvertUint64VectorToSizetVector(const std::vector<std::uint64_t> &in,
  */
 std::vector<std::size_t> Uint64ArrayToSizetVector(const std::size_t nElements,
                                                   const uint64_t *in);
-
 /**
  * Converts a vector of dimensions to a CSV string
  * @param dims vector of dimensions