diff --git a/libserialport.h.in b/libserialport.h.in
index f58530c..678a6fa 100644
--- a/libserialport.h.in
+++ b/libserialport.h.in
@@ -132,16 +132,23 @@ enum {
 	SP_XONXOFF_INOUT = 3
 };
 
+/* Enumeration */
 int sp_get_port_by_name(const char *portname, struct sp_port **port_ptr);
 void sp_free_port(struct sp_port *port);
 int sp_list_ports(struct sp_port ***list_ptr);
 int sp_copy_port(const struct sp_port *port, struct sp_port **copy_ptr);
 void sp_free_port_list(struct sp_port **ports);
+
+/* Opening & closing ports */
 int sp_open(struct sp_port *port, int flags);
 int sp_close(struct sp_port *port);
-int sp_flush(struct sp_port *port);
-int sp_write(struct sp_port *port, const void *buf, size_t count);
+
+/* Reading, writing and flushing. */
 int sp_read(struct sp_port *port, void *buf, size_t count);
+int sp_write(struct sp_port *port, const void *buf, size_t count);
+int sp_flush(struct sp_port *port);
+
+/* Port configuration */
 int sp_set_config(struct sp_port *port, struct sp_port_config *config);
 int sp_set_baudrate(struct sp_port *port, int baudrate);
 int sp_set_bits(struct sp_port *port, int bits);
@@ -152,6 +159,8 @@ int sp_set_cts(struct sp_port *port, int cts);
 int sp_set_dtr(struct sp_port *port, int dtr);
 int sp_set_dsr(struct sp_port *port, int dsr);
 int sp_set_xon_xoff(struct sp_port *port, int xon_xoff);
+
+/* Error handling */
 int sp_last_error_code(void);
 char *sp_last_error_message(void);
 void sp_free_error_message(char *message);