Added checks for the return values of SANE API functions.

src/gtkglue.c

@@ -41,6 +41,16 @@
 #include <sane/sane.h>
 #include <sane/saneopts.h>
 
+#define DBG_fatal 0
+#define DBG_error 1
+#define DBG_warning 2
+#define DBG_info 3
+#define DBG_debug 4
+
+#define DEBUG_NOT_STATIC
+#define BACKEND_NAME xscanimage
+#include "../include/sane/sanei_debug.h"
+
 int gsg_message_dialog_active = 0;
 
 /* forward declarations: */
@@ -425,6 +435,7 @@ scale_update (GtkAdjustment * adj_data, GSGDialogElement * elem)
   SANE_Word val, new_val;
   int opt_num;
   double d;
+  SANE_Status status;
 
   opt_num = elem - dialog->element;
   opt = sane_get_option_descriptor (dialog->dev, opt_num);
@@ -446,8 +457,14 @@ scale_update (GtkAdjustment * adj_data, GSGDialogElement * elem)
       return;
     }
   set_option (dialog, opt_num, &val, SANE_ACTION_SET_VALUE);
-  sane_control_option (dialog->dev, opt_num, SANE_ACTION_GET_VALUE, &new_val,
-		       0);
+  status = sane_control_option (dialog->dev, opt_num, SANE_ACTION_GET_VALUE, &new_val,
+				0);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_fatal, "scale_update: sane_control_option failed: %s\n", sane_strstatus (status));
+      return;
+    }
+
   if (new_val != val)
     {
       val = new_val;

src/preview.c

@@ -79,6 +79,16 @@
 #include "preview.h"
 #include "preferences.h"
 
+#define DBG_fatal 0
+#define DBG_error 1
+#define DBG_warning 2
+#define DBG_info 3
+#define DBG_debug 4
+
+#define DEBUG_DECLARE_ONLY
+#define BACKEND_NAME xscanimage
+#include "../include/sane/sanei_debug.h"
+
 #ifndef PATH_MAX
 # define PATH_MAX	1024
 #endif
@@ -497,12 +507,19 @@ static void
 set_option_bool (Preview *p, int option, SANE_Bool value)
 {
   SANE_Handle dev;
+  SANE_Status status;
 
   if (option <= 0)
     return;
 
   dev = p->dialog->dev;
-  sane_control_option (dev, option, SANE_ACTION_SET_VALUE, &value, 0);
+  status = sane_control_option (dev, option, SANE_ACTION_SET_VALUE, &value, 0);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_fatal, "set_option_bool: sane_control_option failed: %s\n",
+	   sane_strstatus (status));
+      return;
+    }
 }
 
 static int

src/xscanimage.c

@@ -45,6 +45,7 @@
 #include <sane/saneopts.h>
 #include "../include/sane/sanei.h"
 
+#define DEBUG_DECLARE_ONLY
 #define BACKEND_NAME xscanimage
 #include "../include/sane/sanei_debug.h"
 
@@ -307,6 +308,7 @@ query (void)
   char name[1024];
   size_t len;
   int i, j;
+  SANE_Status status;
 
   DBG(DBG_debug, "query\n");
   gimp_install_procedure (
@@ -323,8 +325,19 @@ query (void)
       nargs, nreturn_vals,
       args, return_vals);
 
-  sane_init (0, 0);
-  sane_get_devices (&devlist, SANE_FALSE);
+  status = sane_init (0, 0);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_fatal, "query: sane_init failed: %s\n", sane_strstatus (status));
+      exit (1);
+    }
+
+  status = sane_get_devices (&devlist, SANE_FALSE);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_fatal, "query: sane_get_devices failed: %s\n", sane_strstatus (status));
+      exit (1);
+    }
 
   for (i = 0; devlist[i]; ++i)
     {
@@ -447,8 +460,8 @@ SANE_Word get_resolution (SANE_Handle dev)
 	    if (strncmp (option_desc->name, SANE_NAME_SCAN_RESOLUTION, 
 			 sizeof(SANE_NAME_SCAN_RESOLUTION)) == 0)
 	      {
-		sane_control_option (dev, i, SANE_ACTION_GET_VALUE,
-				     &resolution, 0);
+		status = sane_control_option (dev, i, SANE_ACTION_GET_VALUE,
+					      &resolution, 0);
 		if (status == SANE_STATUS_GOOD) 
 		  {
 		    if (option_desc->type == SANE_TYPE_INT)
@@ -1954,6 +1967,7 @@ init (int argc, char **argv)
 {
   char filename[PATH_MAX];
   struct stat st;
+  SANE_Status status;
 
   DBG(DBG_debug, "init\n");
   gtk_init (&argc, &argv);
@@ -1981,7 +1995,12 @@ init (int argc, char **argv)
 	gtk_rc_parse (filename);
     }
 
-  sane_init (0, 0);
+  status = sane_init (0, 0);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_fatal, "init: sane_init failed: %s\n", sane_strstatus (status));
+      exit (1);
+    }
 
   if (argc > 1)
     {
@@ -2025,7 +2044,13 @@ init (int argc, char **argv)
     {
       char * defdevname;
 
-      sane_get_devices (&devlist, SANE_FALSE);
+      status = sane_get_devices (&devlist, SANE_FALSE);
+      if (status != SANE_STATUS_GOOD)
+	{
+	  DBG (DBG_fatal, "init: sane_get_devices failed: %s\n", sane_strstatus (status));
+	  exit (1);
+	}
+
       if ((defdevname = getenv("SANE_DEFAULT_DEVICE")) != NULL)
 	{
 	  int i;