diff --git a/src/xrt/state_trackers/oxr/CMakeLists.txt b/src/xrt/state_trackers/oxr/CMakeLists.txt
index 446f0580d..fc4c55bb5 100644
--- a/src/xrt/state_trackers/oxr/CMakeLists.txt
+++ b/src/xrt/state_trackers/oxr/CMakeLists.txt
@@ -19,12 +19,12 @@ set(OXR_SOURCE_FILES
 	oxr_api_verify.h
 	oxr_binding.c
 	oxr_chain.h
-	oxr_event.cpp
+	oxr_event.c
 	oxr_extension_support.h
 	oxr_handle_base.c
 	oxr_input.c
 	oxr_instance.c
-	oxr_logger.cpp
+	oxr_logger.c
 	oxr_logger.h
 	oxr_objects.h
 	oxr_path.c
diff --git a/src/xrt/state_trackers/oxr/meson.build b/src/xrt/state_trackers/oxr/meson.build
index 0446b97b6..46bed2cb7 100644
--- a/src/xrt/state_trackers/oxr/meson.build
+++ b/src/xrt/state_trackers/oxr/meson.build
@@ -20,7 +20,7 @@ lib_st_oxr = static_library(
 		'oxr_handle_base.c',
 		'oxr_input.c',
 		'oxr_instance.c',
-		'oxr_logger.cpp',
+		'oxr_logger.c',
 		'oxr_logger.h',
 		'oxr_objects.h',
 		'oxr_path.c',
diff --git a/src/xrt/state_trackers/oxr/oxr_logger.cpp b/src/xrt/state_trackers/oxr/oxr_logger.c
similarity index 97%
rename from src/xrt/state_trackers/oxr/oxr_logger.cpp
rename to src/xrt/state_trackers/oxr/oxr_logger.c
index b0d9b11fd..5eb7abbd4 100644
--- a/src/xrt/state_trackers/oxr/oxr_logger.cpp
+++ b/src/xrt/state_trackers/oxr/oxr_logger.c
@@ -137,7 +137,7 @@ oxr_slog_ensure(struct oxr_sink_logger *slog, size_t extra)
 	slog->store = (char *)realloc(slog->store, slog->store_size);
 }
 
-extern "C" void
+void
 oxr_slog(struct oxr_sink_logger *slog, const char *fmt, ...)
 {
 	va_list args;
@@ -162,7 +162,7 @@ oxr_slog(struct oxr_sink_logger *slog, const char *fmt, ...)
 	slog->length += ret;
 }
 
-extern "C" void
+void
 oxr_slog_free(struct oxr_sink_logger *slog)
 {
 	free(slog->store);
@@ -170,21 +170,21 @@ oxr_slog_free(struct oxr_sink_logger *slog)
 	slog->store_size = 0;
 }
 
-extern "C" void
+void
 oxr_log_slog(struct oxr_logger *log, struct oxr_sink_logger *slog)
 {
 	oxr_log(log, "%s", slog->store);
 	oxr_slog_free(slog);
 }
 
-extern "C" void
+void
 oxr_warn_slog(struct oxr_logger *log, struct oxr_sink_logger *slog)
 {
 	oxr_warn(log, "%s", slog->store);
 	oxr_slog_free(slog);
 }
 
-extern "C" XrResult
+XrResult
 oxr_error_slog(struct oxr_logger *log,
                XrResult res,
                struct oxr_sink_logger *slog)