Move serial line control error checks to lower level routines

Moved in preference to introducing errno.h into rig.c.

src/rig.c

@@ -537,10 +537,6 @@ int HAMLIB_API rig_open(RIG *rig)
           status = ser_set_dtr(&rs->pttport, RIG_PTT_OFF);
         else if (rs->pttport.type.ptt == RIG_PTT_SERIAL_RTS)
           status = ser_set_rts(&rs->pttport, RIG_PTT_OFF);
-        if (status != RIG_OK)
-          {
-            rig_debug(RIG_DEBUG_ERR, "%s: Cannot set serial control line - %s\n", __func__, strerror(errno));
-          }
       }
 	  break;
 	case RIG_PTT_PARALLEL:

src/serial.c

@@ -430,22 +430,29 @@ int ser_close(hamlib_port_t *p)
 int HAMLIB_API ser_set_rts(hamlib_port_t *p, int state)
 {
 	unsigned int y = TIOCM_RTS;
+  int rc;
 
   rig_debug(RIG_DEBUG_VERBOSE, "%s: RTS=%d\n", __func__, state);
 
 #if defined(TIOCMBIS) && defined(TIOCMBIC)
-	return IOCTL(p->fd, state ? TIOCMBIS : TIOCMBIC, &y) < 0 ?
+	rc = IOCTL(p->fd, state ? TIOCMBIS : TIOCMBIC, &y);
-			-RIG_EIO : RIG_OK;
 #else
-	if (IOCTL(p->fd, TIOCMGET, &y) < 0) {
+	rc = IOCTL(p->fd, TIOCMGET, &y);
-		return -RIG_EIO;
+  if (rc >= 0)
-	}
+    {
       if (state)
         y |= TIOCM_RTS;
       else
         y &= ~TIOCM_RTS;
-	return IOCTL(p->fd, TIOCMSET, &y) < 0 ? -RIG_EIO : RIG_OK;
+      rc = IOCTL(p->fd, TIOCMSET, &y);
+    }
 #endif
+  if (rc < 0)
+    {
+      rig_debug(RIG_DEBUG_ERR, "%s: Cannot change RTS - %s\n", __func__, strerror(errno));
+      return -RIG_EIO;
+    }
+  return RIG_OK;
 }
 
 /**
@@ -473,22 +480,29 @@ int HAMLIB_API ser_get_rts(hamlib_port_t *p, int *state)
 int HAMLIB_API ser_set_dtr(hamlib_port_t *p, int state)
 {
 	unsigned int y = TIOCM_DTR;
+  int rc;
 
   rig_debug(RIG_DEBUG_VERBOSE, "%s: DTR=%d\n", __func__, state);
 
 #if defined(TIOCMBIS) && defined(TIOCMBIC)
-	return IOCTL(p->fd, state ? TIOCMBIS : TIOCMBIC, &y) < 0 ?
+	rc = IOCTL(p->fd, state ? TIOCMBIS : TIOCMBIC, &y);
-			-RIG_EIO : RIG_OK;
 #else
-	if (IOCTL(p->fd, TIOCMGET, &y) < 0) {
+	rc = IOCTL(p->fd, TIOCMGET, &y);
-		return -RIG_EIO;
+  if (rc >= 0)
-	}
+    {
       if (state)
         y |= TIOCM_DTR;
       else
         y &= ~TIOCM_DTR;
-	return IOCTL(p->fd, TIOCMSET, &y) < 0 ? -RIG_EIO : RIG_OK;
+      rc = IOCTL(p->fd, TIOCMSET, &y);
+    }
 #endif
+  if (rc < 0)
+    {
+      rig_debug(RIG_DEBUG_ERR, "%s: Cannot change DTR - %s\n", __func__, strerror(errno));
+      return -RIG_EIO;
+    }
+  return RIG_OK;
 }
 
 /**