From 1433efcba69fef54ed6d75b480ae222332ccb989 Mon Sep 17 00:00:00 2001
From: "Eric S. Raymond" <esr@thyrsus.com>
Date: Sun, 24 Aug 2014 10:35:07 -0400
Subject: A lesson in why not to write code with easy-to-miss side effects.

In the Trimble driver, the id field of the sentence was extracted
inside a sprint we needed to remove to get rid of tag field uses.

All regressuin tests pass.
---
 driver_tsip.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

(limited to 'driver_tsip.c')

diff --git a/driver_tsip.c b/driver_tsip.c
index d731f191..cb8b2696 100644
--- a/driver_tsip.c
+++ b/driver_tsip.c
@@ -162,9 +162,7 @@ static gps_mask_t tsip_parse_input(struct gps_device_t *session)
     }
     /*@ -charint @*/
 
-    (void)snprintf(session->tag, sizeof(session->tag),
-		   "ID%02x", id = (unsigned)session->packet.outbuffer[1]);
-
+    id = (unsigned)session->packet.outbuffer[1];
     gpsd_report(session->context->debug, LOG_DATA,
 		"TSIP packet id 0x%02x length %d: %s\n",
 		id, len, buf2);
@@ -196,9 +194,6 @@ static gps_mask_t tsip_parse_input(struct gps_device_t *session)
 	 */
 	u1 = (uint8_t) getub(buf, 0); 
 	if (u1 == 0x81) { /* Software Version Information */
-		(void)snprintf(session->tag + strlen(session->tag), 
-			sizeof(session->tag) -
-			strlen(session->tag), "%02x", (uint) u1);
 		u2 = getub(buf, 2); /* Major version */
 		u3 = getub(buf, 3); /* Minor version */
 		u4 = getub(buf, 4); /* Build number */
@@ -223,9 +218,6 @@ static gps_mask_t tsip_parse_input(struct gps_device_t *session)
 		mask |= DEVICEID_SET;
 	}
 	if (u1 == 0x83) { /* Hardware Version Information */
-		(void)snprintf(session->tag + strlen(session->tag), 
-			sizeof(session->tag) -
-			strlen(session->tag), "%02x", (uint) u1);
 		ul1 = getbeu32(buf, 1); /* Serial number */
 		u2 = getub(buf, 5); /* Build day */
 		u3 = getub(buf, 6); /* Build month */
@@ -667,9 +659,6 @@ static gps_mask_t tsip_parse_input(struct gps_device_t *session)
     case 0x8f:			/* Super Packet.  Well...  */
 	/*@ +charint @*/
 	u1 = (uint8_t) getub(buf, 0);
-	(void)snprintf(session->tag + strlen(session->tag),
-		       sizeof(session->tag) -
-		       strlen(session->tag), "%02x", (uint) u1);
 	/*@ -charint @*/
 	switch (u1) {		/* sub-packet ID */
 	case 0x15:		/* Current Datum Values */
-- 
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