diff --git a/cmake/tests.cmake b/cmake/tests.cmake
index 2519ea9..2b62002 100644
--- a/cmake/tests.cmake
+++ b/cmake/tests.cmake
@@ -44,7 +44,6 @@ add_test(NAME zimtohrli_loudness_computation_ipynb_test
     WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
 )
 
-
 add_test(NAME zimtohrli_go_test
     COMMAND go test ./...
     WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
diff --git a/cpp/zimt/visqol.cc b/cpp/zimt/visqol.cc
index 53f640e..0397d20 100644
--- a/cpp/zimt/visqol.cc
+++ b/cpp/zimt/visqol.cc
@@ -14,7 +14,13 @@
 
 #include "zimt/visqol.h"
 
-#include <iostream>
+#include <cerrno>
+#include <cstring>
+#include <filesystem>
+#include <fstream>
+#include <random>
+#include <string>
+#include <vector>
 
 #include "absl/log/check.h"
 #include "absl/types/span.h"
@@ -27,13 +33,14 @@ constexpr size_t SAMPLE_RATE = 48000;
 namespace zimtohrli {
 
 ViSQOL::ViSQOL() {
-  std::string path_template = (std::filesystem::path(std::string(P_tmpdir)) /
+  std::string path_template = (std::filesystem::temp_directory_path() /
                                "zimtohrli_cpp_zimt_visqol_model_XXXXXX")
                                   .string();
   std::vector<char> populated_path_template(path_template.begin(),
                                             path_template.end());
-  int model_path_file = mkstemp(populated_path_template.data());
-  CHECK_GT(model_path_file, 0);
+  populated_path_template.push_back('\0');
+  const int model_path_file = mkstemp(populated_path_template.data());
+  CHECK_GT(model_path_file, 0) << strerror(errno);
   CHECK_EQ(close(model_path_file), 0);
   model_path_ = std::filesystem::path(std::string(
       populated_path_template.data(), populated_path_template.size()));
diff --git a/cpp/zimt/visqol_model.cc b/cpp/zimt/visqol_model.cc
index ea5afc6..ccdc5c2 100644
--- a/cpp/zimt/visqol_model.cc
+++ b/cpp/zimt/visqol_model.cc
@@ -19,7 +19,7 @@
 
 namespace zimtohrli {
 
-absl::Span<char> ViSQOLModel() {
+absl::Span<const char> ViSQOLModel() {
   return absl::Span<char>(reinterpret_cast<char*>(visqol_model_bytes),
                           visqol_model_bytes_len);
 }
diff --git a/cpp/zimt/visqol_model.h b/cpp/zimt/visqol_model.h
index f4479aa..32d308c 100644
--- a/cpp/zimt/visqol_model.h
+++ b/cpp/zimt/visqol_model.h
@@ -20,7 +20,7 @@
 namespace zimtohrli {
 
 // Returns the bytes of the default ViSQOL model.
-absl::Span<char> ViSQOLModel();
+absl::Span<const char> ViSQOLModel();
 
 }  // namespace zimtohrli
 
diff --git a/go/goohrli/goohrli.a b/go/goohrli/goohrli.a
index 733e8fc..963ed43 100644
Binary files a/go/goohrli/goohrli.a and b/go/goohrli/goohrli.a differ