fixed issue with invalid devices; refs #30

src/pcsc.hxx

@@ -486,13 +486,20 @@ namespace pcsc {
           @returns list of readers that contain @c atr in their ATR */
       static Strings getReadersWithAtr(const std::string& atr,
                                        Scope s=USER, bool exceptions=true) {
+        CRYPTOLOG("getting all readers with atr: "<<atr);
         Connection c(s, exceptions);
         Strings res;
         pcsc::Connection::Strings readers(c.scan());
         for (pcsc::Connection::Strings::const_iterator it(readers.begin());
              it!=readers.end(); ++it)
-          if (crypto::hex(c.reader(*it)->status().atr).find(atr)!=string::npos)
+          try {
+            if (crypto::hex(c.reader(*it)->status().atr).find(atr)
+                !=string::npos)
+              CRYPTOLOG("found reader: "<<*it);
               res.push_back(*it);
+          } catch (std::exception& x) { // ignore unusable readers
+            CRYPTOLOG("ignored unusable reader: "<<x.what());
+          }
         return res;
       }