Increase serial timeout lengths. Mostly for benefit of Magic Control

Technologies USB/serial port adapters which appear to get this slightly
wrong.

Better display of Windows system call errors.

diff --git a/gpsbabel/jeeps/gpsserial.c b/gpsbabel/jeeps/gpsserial.c
index 9f967edda7e21eca31c63aebee3e2d9427696dd1..d0aa4631e6a4d5af117e5fd3fdff948addb4f431 100644 (file)
--- a/gpsbabel/jeeps/gpsserial.c
+++ b/gpsbabel/jeeps/gpsserial.c
@@ -61,6 +61,21 @@ char *rxdata[] = {
  *  internal.   This means we ignore that 'fd' number that gets passed in.
  */
 
+void GPS_Serial_Error(char *hdr)
+{
+       char msg[200];
+       char *s;
+
+       strcpy(msg, hdr);
+       s = msg + strlen(hdr);
+       *s++ = ':';
+       *s++ = ' ';
+
+       FormatMessage( FORMAT_MESSAGE_FROM_SYSTEM, 0, 
+                       GetLastError(), 0, s, sizeof(msg) - strlen(hdr) - 2, 0 );
+       GPS_Error(msg);
+}
+
 static HANDLE comport;
 
 int32 GPS_Serial_On(const char *port, int32 *fd)
@@ -70,7 +85,9 @@ int32 GPS_Serial_On(const char *port, int32 *fd)
 
        comport = CreateFile(port, GENERIC_READ|GENERIC_WRITE, 0, NULL,
                                          OPEN_EXISTING, 0, NULL);
+
        if (comport == INVALID_HANDLE_VALUE) {
+               GPS_Serial_Error("CreateFile");
                gps_errno = SERIAL_ERROR;
                return 0;
        }
@@ -96,18 +113,26 @@ int32 GPS_Serial_On(const char *port, int32 *fd)
        tio.StopBits = ONESTOPBIT;
 
        if (!SetCommState (comport, &tio)) {
+               GPS_Serial_Error("SetCommState");
                CloseHandle(comport);
                gps_errno = SERIAL_ERROR;
                return 0;
        }
 
+       /*
+        * The timeouts are kind of fictional as we always end up doing
+        * single byte reads.   At 9600bps (the default) the individual
+        * character time is 104Millisecs, so these are mostly "dead-man"
+        * (i.e. cable unplugged, unit not turned on) values.
+        */
        GetCommTimeouts (comport, &timeout);
-       timeout.ReadIntervalTimeout = 10;
-       timeout.ReadTotalTimeoutMultiplier = 10;
+       timeout.ReadIntervalTimeout = 1000; /*like vtime.  In MS. */
+       timeout.ReadTotalTimeoutMultiplier = 1000;
        timeout.ReadTotalTimeoutConstant = 1000;
-       timeout.WriteTotalTimeoutMultiplier = 10;
+       timeout.WriteTotalTimeoutMultiplier = 1000;
        timeout.WriteTotalTimeoutConstant = 1000;
        if (!SetCommTimeouts (comport, &timeout)) {
+               GPS_Serial_Error("SetCommTimeouts");
                CloseHandle (comport);
                gps_errno = SERIAL_ERROR;
                return 0;
@@ -149,7 +174,7 @@ int32 GPS_Serial_Write(int32 ignored, const void *obuf, int size)
 
 int32 GPS_Serial_Read(int32 ignored, void *ibuf, int size)
 {
-       DWORD cnt;
+       DWORD cnt  = 0;
 
        ReadFile(comport, ibuf, size, &cnt, NULL);
        return cnt;