Fix SANE_Pid related -Wsign-compare warnings

This may fix threading related issues on WIN32 platforms, BTW.

backend/agfafocus.c

@@ -947,7 +947,7 @@ do_cancel (AgfaFocus_Scanner * s)
 
   do_eof (s);
 
-  if (s->reader_pid != -1)
+  if (!sanei_thread_is_invalid (s->reader_pid))
     {
       int exit_status;
 
@@ -2054,7 +2054,7 @@ sane_cancel (SANE_Handle handle)
 {
   AgfaFocus_Scanner *s = handle;
 
-  if (s->reader_pid != -1)
+  if (!sanei_thread_is_invalid (s->reader_pid))
     sanei_thread_kill (s->reader_pid);
   s->scanning = SANE_FALSE;
 }

backend/artec_eplus48u.c

@@ -3483,7 +3483,7 @@ do_cancel (Artec48U_Scanner * s, SANE_Bool closepipe)
 
   s->scanning = SANE_FALSE;
 
-  if (s->reader_pid != -1)
+  if (!sanei_thread_is_invalid (s->reader_pid))
     {
       /*parent */
       XDBG ((1, "killing reader_process\n"));
@@ -4301,7 +4301,7 @@ sane_start (SANE_Handle handle)
   s->reader_pipe = fds[1];
   s->reader_pid = sanei_thread_begin (reader_process, s);
   cancelRead = SANE_FALSE;
-  if (s->reader_pid == -1)
+  if (sanei_thread_is_invalid (s->reader_pid))
     {
       s->scanning = SANE_FALSE;
       XDBG ((2, "sane_start: sanei_thread_begin failed (%s)\n", strerror (errno)));

backend/avision.c

@@ -6216,7 +6216,7 @@ do_cancel (Avision_Scanner* s)
   s->duplex_rear_valid = SANE_FALSE;
   s->page = 0;
   
-  if (s->reader_pid != -1) {
+  if (!sanei_thread_is_invalid (s->reader_pid)) {
     int exit_status;
     
     /* ensure child knows it's time to stop: */

backend/coolscan.c

@@ -2029,7 +2029,7 @@ do_cancel (Coolscan_t * scanner)
 
   do_eof (scanner);		/* close pipe and reposition scanner */
 
-  if (scanner->reader_pid != -1)
+  if (!sanei_thread_is_invalid (scanner->reader_pid))
     {
       int exit_status;
 
@@ -4093,7 +4093,7 @@ sane_start (SANE_Handle handle)
   scanner->pipe       = fds[0];
   scanner->reader_fds = fds[1];
   scanner->reader_pid = sanei_thread_begin( reader_process, (void*)scanner );
-  if (scanner->reader_pid == -1)
+  if (sanei_thread_is_invalid (scanner->reader_pid))
     {
       DBG (1, "sane_start: sanei_thread_begin failed (%s)\n",
              strerror (errno));
@@ -4153,7 +4153,7 @@ sane_cancel (SANE_Handle handle)
 {
   Coolscan_t *s = handle;
 
-  if (s->reader_pid != -1)
+  if (!sanei_thread_is_invalid (s->reader_pid))
     {
       sanei_thread_kill   ( s->reader_pid );
       sanei_thread_waitpid( s->reader_pid, NULL );

backend/hp-handle.c

@@ -192,7 +192,7 @@ hp_handle_startReader (HpHandle this, HpScsi scsi)
         this->pipe_write_fd = -1;
       }
 
-      if (this->reader_pid == -1)  /* Creating child failed ? Clean up pipe */
+      if (sanei_thread_is_invalid (this->reader_pid))
 	{
           if ( !this->child_forked )
           {

backend/hp3500.c

@@ -703,7 +703,7 @@ sane_start (SANE_Handle handle)
   scanner->reader_pid = sanei_thread_begin (reader_process, scanner);
   time (&scanner->last_scan);
 
-  if (scanner->reader_pid == -1)
+  if (sanei_thread_is_invalid (scanner->reader_pid))
     {
       DBG (MSG_ERR, "cannot fork reader process.\n");
       DBG (MSG_ERR, "%s", strerror (errno));
@@ -1098,7 +1098,7 @@ do_reset (struct hp3500_data *scanner)
 static void
 do_cancel (struct hp3500_data *scanner)
 {
-  if (scanner->reader_pid != -1)
+  if (!sanei_thread_is_invalid (scanner->reader_pid))
     {
 
       if (sanei_thread_kill (scanner->reader_pid) == 0)

backend/microtek2.c

@@ -909,7 +909,7 @@ cancel_scan(Microtek2_Scanner *ms)
        of material on a feeder, then pid may be already -1 and
        kill(-1, SIGTERM), i.e. killing all our processes, is not
        likely what we really want - --mj, 2001/Nov/19 */
-    if (ms->pid != -1)
+    if (!sanei_thread_is_invalid (ms->pid))
       {
        sanei_thread_kill(ms->pid);
        sanei_thread_waitpid(ms->pid, NULL);
@@ -5503,7 +5503,7 @@ sane_start(SANE_Handle handle)
     /* create reader routine as new thread or process */
     ms->pid = sanei_thread_begin( reader_process,(void*) ms);
 
-    if ( ms->pid == -1 )
+    if ( sanei_thread_is_invalid (ms->pid) )
       {
         DBG(1, "sane_start: fork failed\n");
         status = SANE_STATUS_IO_ERROR;

backend/mustek.c

@@ -2952,7 +2952,7 @@ do_stop (Mustek_Scanner * s)
   s->scanning = SANE_FALSE;
   s->pass = 0;
 
-  if (s->reader_pid != -1)
+  if (!sanei_thread_is_invalid (s->reader_pid))
     {
       SANE_Int exit_status;
       struct timeval now;
@@ -2983,7 +2983,7 @@ do_stop (Mustek_Scanner * s)
       sanei_thread_kill (s->reader_pid);
 
       pid = sanei_thread_waitpid (s->reader_pid, &exit_status);
-      if (pid == -1)
+      if (sanei_thread_is_invalid (pid))
 	{
 	  DBG (1,
 	       "do_stop: sanei_thread_waitpid failed, already terminated? (%s)\n",
@@ -6565,7 +6565,7 @@ sane_start (SANE_Handle handle)
   /* create reader routine as new process or thread */
   s->reader_pid = sanei_thread_begin (reader_process, (void *) s);
 
-  if (s->reader_pid == -1)
+  if (sanei_thread_is_invalid (s->reader_pid))
     {
       DBG (1, "sane_start: sanei_thread_begin failed (%s)\n",
 	   strerror (errno));

backend/pie.c

@@ -2896,7 +2896,7 @@ do_cancel (Pie_Scanner * scanner)
 
   scanner->scanning = SANE_FALSE;
 
-  if (scanner->reader_pid != -1)
+  if (!sanei_thread_is_invalid (scanner->reader_pid))
     {
       DBG (DBG_sane_info, "killing reader_process\n");
       sanei_thread_kill (scanner->reader_pid);
@@ -3703,7 +3703,7 @@ sane_start (SANE_Handle handle)
   scanner->reader_fds = fds[1];
   scanner->reader_pid = sanei_thread_begin( reader_process, (void*)scanner );
 
-  if (scanner->reader_pid == -1)
+  if (sanei_thread_is_invalid (scanner->reader_pid))
     {
       DBG (1, "sane_start: sanei_thread_begin failed (%s)\n",
              strerror (errno));

backend/pixma.c

@@ -1083,7 +1083,7 @@ terminate_reader_task (pixma_sane_t * ss, int *exit_code)
   int status = 0;
 
   pid = ss->reader_taskid;
-  if (pid == -1)
+  if (sanei_thread_is_invalid (pid))
     return -1;
   if (sanei_thread_is_forked ())
     {
@@ -1129,7 +1129,7 @@ start_reader_task (pixma_sane_t * ss)
       ss->rpipe = -1;
       ss->wpipe = -1;
     }
-  if (ss->reader_taskid != -1)
+  if (!sanei_thread_is_invalid (ss->reader_taskid))
     {
       PDBG (pixma_dbg
 	    (1, "BUG:reader_taskid(%ld) != -1\n", (long) ss->reader_taskid));
@@ -1159,7 +1159,7 @@ start_reader_task (pixma_sane_t * ss)
     {
       pid = sanei_thread_begin (reader_thread, ss);
     }
-  if (pid == -1)
+  if (sanei_thread_is_invalid (pid))
     {
       close (ss->wpipe);
       close (ss->rpipe);
@@ -1227,7 +1227,7 @@ read_image (pixma_sane_t * ss, void *buf, unsigned size, int *readlen)
 		       ss->image_bytes_read, ss->sp.image_size));
       close (ss->rpipe);
       ss->rpipe = -1;
-      if (terminate_reader_task (ss, &status) != -1
+      if (!sanei_thread_is_invalid (terminate_reader_task (ss, &status))
       	  && status != SANE_STATUS_GOOD)
         {
           return status;

backend/plustek.c

@@ -572,7 +572,7 @@ do_cancel( Plustek_Scanner *scanner, SANE_Bool closepipe )
 	DBG( _DBG_PROC,"do_cancel\n" );
 	scanner->scanning = SANE_FALSE;
 
-	if( scanner->reader_pid != -1 ) {
+	if( !sanei_thread_is_invalid (scanner->reader_pid) ) {
 
 		DBG( _DBG_PROC, ">>>>>>>> killing reader_process <<<<<<<<\n" );
 
@@ -2629,7 +2629,7 @@ sane_start( SANE_Handle handle )
 
 	cancelRead = SANE_FALSE;
 	
-	if( s->reader_pid == -1 ) {
+	if( sanei_thread_is_invalid (s->reader_pid) ) {
 		DBG( _DBG_ERROR, "ERROR: could not start reader task\n" );
 		s->scanning = SANE_FALSE;
 		usbDev_close( dev );

backend/snapscan.c

@@ -1301,7 +1301,7 @@ static SANE_Status start_reader (SnapScan_Scanner *pss)
 
         cancelRead = SANE_FALSE;
 
-        if (pss->child == -1)
+        if (sanei_thread_is_invalid (pss->child))
         {
             /* we'll have to read in blocking mode */
             DBG (DL_MAJOR_ERROR,
@@ -1815,7 +1815,7 @@ SANE_Status sane_read (SANE_Handle h,
 
     if (pss->psrc == NULL  ||  pss->psrc->remaining(pss->psrc) == 0)
     {
-        if (pss->child != -1)
+      if (!sanei_thread_is_invalid (pss->child))
         {
             sanei_thread_waitpid (pss->child, 0);        /* ensure no zombies */
             pss->child = -1;
@@ -1875,7 +1875,7 @@ void sane_cancel (SANE_Handle h)
         /* signal a cancellation has occurred */
         pss->state = ST_CANCEL_INIT;
         /* signal the reader, if any */
-        if (pss->child != -1)
+        if (!sanei_thread_is_invalid (pss->child))
         {
             DBG( DL_INFO, ">>>>>>>> killing reader_process <<<<<<<<\n" );
 
@@ -1941,7 +1941,7 @@ SANE_Status sane_set_io_mode (SANE_Handle h, SANE_Bool m)
 
     if (m)
     {
-        if (pss->child == -1)
+      if (sanei_thread_is_invalid (pss->child))
         {
             DBG (DL_MINOR_INFO,
                  "%s: no reader child; must use blocking mode.\n",
@@ -1971,7 +1971,7 @@ SANE_Status sane_get_select_fd (SANE_Handle h, SANE_Int * fd)
     if (pss->state != ST_SCAN_INIT)
         return SANE_STATUS_INVAL;
 
-    if (pss->child == -1)
+    if (sanei_thread_is_invalid (pss->child))
     {
         DBG (DL_MINOR_INFO,
              "%s: no reader child; cannot provide select file descriptor.\n",

backend/sp15c.c

@@ -1762,7 +1762,7 @@ do_cancel (struct sp15c *scanner)
 
   do_eof (scanner);             /* close pipe and reposition scanner */
 
-  if (scanner->reader_pid != -1)
+  if (!sanei_thread_is_invalid (scanner->reader_pid))
     {
       int exit_status;
       DBG (10, "do_cancel: kill reader_process\n");

backend/tamarack.c

@@ -470,7 +470,7 @@ do_cancel (Tamarack_Scanner *s)
 
   do_eof (s);
 
-  if (s->reader_pid != -1)
+  if (!sanei_thread_is_invalid (s->reader_pid))
     {
       int exit_status;
 
@@ -1442,7 +1442,7 @@ sane_cancel (SANE_Handle handle)
 {
   Tamarack_Scanner *s = handle;
 
-  if (s->reader_pid != -1)
+  if (!sanei_thread_is_invalid (s->reader_pid))
     sanei_thread_kill (s->reader_pid);
   s->scanning = SANE_FALSE;
 }

backend/test.c

@@ -1355,7 +1355,7 @@ finish_pass (Test_Device * test_device)
       DBG (2, "finish_pass: pipe closed\n");
       test_device->pipe = -1;
     }
-  if (test_device->reader_pid != -1)
+  if (!sanei_thread_is_invalid (test_device->reader_pid))
     {
       int status;
       SANE_Pid pid;
@@ -1364,7 +1364,7 @@ finish_pass (Test_Device * test_device)
 	   (long) test_device->reader_pid);
       sanei_thread_kill (test_device->reader_pid);
       pid = sanei_thread_waitpid (test_device->reader_pid, &status);
-      if (pid == -1)
+      if (sanei_thread_is_invalid (pid))
 	{
 	  DBG (1,
 	       "finish_pass: sanei_thread_waitpid failed, already terminated? (%s)\n",
@@ -2568,7 +2568,7 @@ sane_start (SANE_Handle handle)
   test_device->reader_pid =
     sanei_thread_begin (reader_task, (void *) test_device);
 
-  if (test_device->reader_pid == -1)
+  if (sanei_thread_is_invalid (test_device->reader_pid))
     {
       DBG (1, "sane_start: sanei_thread_begin failed (%s)\n",
 	   strerror (errno));

backend/u12.c

@@ -391,7 +391,7 @@ static SANE_Status do_cancel( U12_Scanner *scanner, SANE_Bool closepipe )
 
 	scanner->scanning = SANE_FALSE;
 
-	if( scanner->reader_pid != -1 ) {
+	if( !sanei_thread_is_invalid (scanner->reader_pid) ) {
 
 		DBG( _DBG_PROC, ">>>>>>>> killing reader_process <<<<<<<<\n" );
 
@@ -1731,7 +1731,7 @@ SANE_Status sane_start( SANE_Handle handle )
 	
 	cancelRead = SANE_FALSE;
 	
-	if( s->reader_pid == -1 ) {
+	if( sanei_thread_is_invalid (s->reader_pid) ) {
 		DBG( _DBG_ERROR, "ERROR: could not start reader task\n" );
 		s->scanning = SANE_FALSE;
 		u12if_close( dev );

backend/umax.c

@@ -4670,14 +4670,14 @@ static SANE_Status do_cancel(Umax_Scanner *scanner)
 
   scanner->scanning = SANE_FALSE;
 
-  if (scanner->reader_pid != -1)
+  if (!sanei_thread_is_invalid (scanner->reader_pid))
   {
     DBG(DBG_sane_info,"killing reader_process\n");
 
     sanei_thread_kill(scanner->reader_pid);
     pid = sanei_thread_waitpid(scanner->reader_pid, &status);
 
-    if (pid == -1)
+    if (sanei_thread_is_invalid (pid))
     {
       DBG(DBG_sane_info, "do_cancel: sanei_thread_waitpid failed, already terminated ? (%s)\n", strerror(errno));
     }
@@ -7996,7 +7996,7 @@ SANE_Status sane_start(SANE_Handle handle)
   /* start reader_process, deponds on OS if fork() or threads are used */
   scanner->reader_pid = sanei_thread_begin(reader_process, (void *) scanner);
 
-  if (scanner->reader_pid == -1)
+  if (sanei_thread_is_invalid (scanner->reader_pid))
   {
     DBG(DBG_error, "ERROR: sanei_thread_begin failed (%s)\n", strerror(errno));
     scanner->scanning = SANE_FALSE;

sanei/sanei_thread.c

@@ -147,7 +147,7 @@ sanei_thread_is_invalid( SANE_Pid pid )
 #endif
 	    rc = SANE_TRUE;
 #else
-	if (pid == -1)
+	if (pid == (SANE_Pid) -1)
 	    rc = SANE_TRUE;
 #endif