diff --git a/project/headers.mk b/project/headers.mk
index d137b03..585234b 100644
--- a/project/headers.mk
+++ b/project/headers.mk
@@ -3,5 +3,6 @@ API_HEADERS = \
 	$(PROJECT_DIR)/include/$(PACKAGE)/sltdl_api.h \
 
 INTERNAL_HEADERS = \
+	$(SOURCE_DIR)/src/internal/sltdl_core.h \
 
 ALL_HEADERS = $(API_HEADERS) $(INTERNAL_HEADERS)
diff --git a/src/core/lt_core.c b/src/core/lt_core.c
index b0c3952..df9f58f 100644
--- a/src/core/lt_core.c
+++ b/src/core/lt_core.c
@@ -38,3 +38,18 @@ int lt_dlexit(void)
 
 	return 0;
 }
+
+void lt_slock(void)
+{
+	int locked;
+
+	do {
+		locked = pthread_mutex_lock(&lt_lock);
+	} while (locked);
+}
+
+int lt_sunlock(int ret)
+{
+	pthread_mutex_unlock(&lt_lock);
+	return ret;
+}
diff --git a/src/internal/sltdl_core.h b/src/internal/sltdl_core.h
new file mode 100644
index 0000000..f74542e
--- /dev/null
+++ b/src/internal/sltdl_core.h
@@ -0,0 +1,7 @@
+#ifndef SLTDL_CORE_H
+#define SLTDL_CORE_H
+
+void lt_slock(void);
+int  lt_sunlock(int);
+
+#endif