diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4e68e465..92702d72 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -207,6 +207,10 @@ FetchContent_Declare(fftw
         URL_HASH SHA256=56c932549852cddcfafdab3820b0200c7742675be92179e59e6215b340e26467
         EXCLUDE_FROM_ALL)
 FetchContent_MakeAvailable(fftw)
+# FFTW exposes fftw3.h only via $<INSTALL_INTERFACE:include>, so consuming fftw3f straight from
+# the build tree (FetchContent) leaves the header unreachable. On Linux a system-installed
+# fftw3.h masks this; on Windows it does not. Add the source-tree api/ dir for build-tree use.
+TARGET_INCLUDE_DIRECTORIES(fftw3f INTERFACE $<BUILD_INTERFACE:${fftw_SOURCE_DIR}/api>)
 ADD_COMPILE_DEFINITIONS(JFJOCH_USE_FFTW)
 
 IF (JFJOCH_VIEWER_ONLY)
diff --git a/common/time_utc.h b/common/time_utc.h
index 4a1067ab..bec55fd7 100644
--- a/common/time_utc.h
+++ b/common/time_utc.h
@@ -27,7 +27,7 @@ inline std::string time_UTC(const std::chrono::time_point<std::chrono::system_cl
         throw std::runtime_error("gmtime failed");
 
     strftime(buf1, sizeof(buf1), "%FT%T", &tm_utc);
-    snprintf(buf2, sizeof(buf2), ".%03ld", time_ms % 1000);
+    snprintf(buf2, sizeof(buf2), ".%03d", static_cast<int>(time_ms % 1000));
     return std::string(buf1) + std::string(buf2) + "Z";
 }
 
diff --git a/writer/HDF5Objects.h b/writer/HDF5Objects.h
index d4945359..ba085b45 100644
--- a/writer/HDF5Objects.h
+++ b/writer/HDF5Objects.h
@@ -264,7 +264,7 @@ public:
         if (file_space.GetNumOfDimensions() != 0)
             throw JFJochException(JFJochExceptionCategory::HDF5, "Dataset tries to read scalar from vector dataset");;
 
-        T output;
+        T output{};
         if (H5Dread(id, HDF5DataType(output).GetID(), mem_space.GetID(), H5S_ALL, H5P_DEFAULT, &output) < 0)
             throw JFJochException(JFJochExceptionCategory::HDF5, dataset_name + ": read unsuccessful");
         return output;