First cut at salience test.

1 files changed, 13 insertions, 1 deletions

diff --git a/gpsd.h-tail b/gpsd.h-tail
index ced2f346..c60c74fc 100644
--- a/gpsd.h-tail
+++ b/gpsd.h-tail
@@ -40,7 +40,7 @@ typedef unsigned int speed_t;
  * 3.8  AIS course nember becomes float in scaled mode (bug fix).
  * 3.9  split24 flag added. Controlled-vocabulary fields are now always
  *      dumped in both numeric and string form, with the string being the
- *      value of a synteshized additional attribute with "_text" appended.
+ *      value of a synthesized additional attribute with "_text" appended.
  *      (Thus, the 'scaled' flag no longer affects display of these fields.)
  */
 #define GPSD_PROTO_MAJOR_VERSION	3	/* bump on incompatible changes */
@@ -297,6 +297,18 @@ typedef enum {
 typedef /*@unsignedintegraltype@*/ unsigned int driver_mask_t;
 #define DRIVER_NOFLAGS	0x00000000u
 
+/*
+ * True if a device type is non-null and has control methods.
+ */
+#define CONTROLLABLE(dp)	(((dp) != NULL) && \
+				 ((dp)->speed_switcher != NULL		\
+				  || (dp)->mode_switcher != NULL	\
+				  || (dp)->rate_switcher != NULL))
+/*
+ * True if a driver is salient and selection of it should be sticky. 
+ */
+#define SALIENT(dp)		(CONTROLLABLE(dp))
+
 struct gps_type_t {
 /* GPS method table, describes how to talk to a particular GPS type */
     /*@observer@*/char *type_name;