Add flushx option for MicroHam devices to allow flushing by read instead of tcflush.

The special name of uh-rig only works on Linux and has other purposes apparently for ptt use
https://github.com/Hamlib/Hamlib/issues/446

include/hamlib/rig.h

@@ -1901,6 +1901,7 @@ typedef struct hamlib_port {
             int value;      /*!< Toggle PTT ON or OFF */
         } gpio;             /*!< GPIO attributes */
     } parm;                 /*!< Port parameter union */
+    int flushx;             /*!< If true flush is done with read instead of TCFLUSH - MicroHam */
 } hamlib_port_t;
 //! @endcond
 

src/conf.c

@@ -143,6 +143,11 @@ static const struct confparams frontend_cfg_params[] =
         "True enables ptt port to be shared with other apps",
         "0", RIG_CONF_CHECKBUTTON, { }
     },
+    {
+        TOK_FLUSHX, "flushx", "Flush with read instead of TCFLUSH",
+        "True enables flushing serial port with read instead of TCFLUSH -- MicroHam",
+        "0", RIG_CONF_CHECKBUTTON, { }
+    },
 
     { RIG_CONF_END, NULL, }
 };
@@ -594,6 +599,14 @@ static int frontend_set_conf(RIG *rig, token_t token, const char *val)
         rs->ptt_share = val_i ? 1 : 0;
         break;
 
+    case TOK_FLUSHX:
+        if (1 != sscanf(val, "%d", &val_i))
+        {
+            return -RIG_EINVAL; //value format error
+        }
+
+        rs->rigport.flushx = val_i ? 1 : 0;
+        break;
 
     default:
         return -RIG_EINVAL;

src/serial.c

@@ -607,7 +607,7 @@ int HAMLIB_API serial_flush(hamlib_port_t *p)
 {
     rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);
 
-    if (p->fd == uh_ptt_fd || p->fd == uh_radio_fd)
+    if (p->fd == uh_ptt_fd || p->fd == uh_radio_fd || p->flushx)
     {
         unsigned char buf[32];
         /*
@@ -615,24 +615,26 @@ int HAMLIB_API serial_flush(hamlib_port_t *p)
          * if fd corresponds to a microHam device drain the line
          * (which is a socket) by reading until it is empty.
          */
-        int n;
+        int n, nbytes=0;
 
-        rig_debug(RIG_DEBUG_TRACE, "%s: flushing: ", __func__);
+        rig_debug(RIG_DEBUG_TRACE, "%s: flushing\n", __func__);
 
         while ((n = read(p->fd, buf, 32)) > 0)
         {
+            nbytes += n;
             //int i;
 
             //for (i = 0; i < n; ++i) { printf("0x%02x(%c) ", buf[i], isprint(buf[i]) ? buf[i] : '~'); }
 
             /* do nothing */
         }
+        rig_debug(RIG_DEBUG_TRACE, "read flushed %d bytes\n", nbytes);
 
 
         return RIG_OK;
     }
 
-    rig_debug(RIG_DEBUG_VERBOSE, "%s: tcflush\n", __func__);
+    rig_debug(RIG_DEBUG_VERBOSE, "tcflush%s\n", "");
     tcflush(p->fd, TCIFLUSH);
     return RIG_OK;
 }

src/token.h

@@ -89,6 +89,8 @@
 #define TOK_PTT_BITNUM        TOKEN_FRONTEND(34)
 /** \brief  PTT share with other applications */
 #define TOK_PTT_SHARE        TOKEN_FRONTEND(35)
+/** \brief  PTT share with other applications */
+#define TOK_FLUSHX        TOKEN_FRONTEND(36)
 /*
  * rig specific tokens
  */