diff --git a/src/DebugLogger.cc b/src/DebugLogger.cc
index 4ff950c377..a7b2a41dfe 100644
--- a/src/DebugLogger.cc
+++ b/src/DebugLogger.cc
@@ -56,7 +56,7 @@ void DebugLogger::OpenDebugLog(const char* filename)
 				}
 			}
 
-		setvbuf(file, NULL, _IOLBF, 0);
+		util::detail::setvbuf(file, NULL, _IOLBF, 0);
 		}
 	else
 		file = stderr;
diff --git a/src/File.cc b/src/File.cc
index 44c78ccd91..864a0cc37f 100644
--- a/src/File.cc
+++ b/src/File.cc
@@ -202,16 +202,8 @@ void File::SetBuf(bool arg_buffered)
 	if ( ! f )
 		return;
 
-#ifndef _MSC_VER
-	if ( setvbuf(f, NULL, arg_buffered ? _IOFBF : _IOLBF, 0) != 0 )
+	if ( util::detail::setvbuf(f, NULL, arg_buffered ? _IOFBF : _IOLBF, 0) != 0 )
 		reporter->Error("setvbuf failed");
-#else
-	// TODO: this turns off buffering altogether because Windows wants us to pass a valid
-	// buffer and length if we're going to pass one of the other modes. We need to
-	// investigate the performance ramifications of this.
-	if ( setvbuf(f, NULL, _IONBF, 0) != 0 )
-		reporter->Error("setvbuf failed");
-#endif
 
 	buffered = arg_buffered;
 	}
diff --git a/src/file_analysis/analyzer/extract/Extract.cc b/src/file_analysis/analyzer/extract/Extract.cc
index 77a696daf3..e6805b867a 100644
--- a/src/file_analysis/analyzer/extract/Extract.cc
+++ b/src/file_analysis/analyzer/extract/Extract.cc
@@ -23,7 +23,7 @@ Extract::Extract(RecordValPtr args, file_analysis::File* file, const std::string
 	if ( file_stream )
 		{
 		// Try to ensure full buffering.
-		if ( setvbuf(file_stream, nullptr, _IOFBF, BUFSIZ) )
+		if ( util::detail::setvbuf(file_stream, nullptr, _IOFBF, BUFSIZ) )
 			{
 			util::zeek_strerror_r(errno, buf, sizeof(buf));
 			reporter->Warning("cannot set buffering mode for %s: %s", filename.data(), buf);