make all catch() arguments const

- I saw this on http://en.cppreference.com/w/cpp/language/try_catch and
  thought it would be a good idea
- also unify used format to better be able to search for exception
  uses in our codebase

src/bitcoin-cli.cpp

@@ -86,7 +86,7 @@ static bool AppInitRPC(int argc, char* argv[])
     }
     try {
         ReadConfigFile(mapArgs, mapMultiArgs);
-    } catch(std::exception &e) {
+    } catch (const std::exception& e) {
         fprintf(stderr,"Error reading configuration file: %s\n", e.what());
         return false;
     }
@@ -206,7 +206,7 @@ int CommandLineRPC(int argc, char *argv[])
                 // Connection succeeded, no need to retry.
                 break;
             }
-            catch (const CConnectionFailed& e) {
+            catch (const CConnectionFailed&) {
                 if (fWait)
                     MilliSleep(1000);
                 else
@@ -214,10 +214,10 @@ int CommandLineRPC(int argc, char *argv[])
             }
         } while (fWait);
     }
-    catch (boost::thread_interrupted) {
+    catch (const boost::thread_interrupted&) {
         throw;
     }
-    catch (std::exception& e) {
+    catch (const std::exception& e) {
         strPrint = string("error: ") + e.what();
         nRet = EXIT_FAILURE;
     }
@@ -240,7 +240,7 @@ int main(int argc, char* argv[])
         if(!AppInitRPC(argc, argv))
             return EXIT_FAILURE;
     }
-    catch (std::exception& e) {
+    catch (const std::exception& e) {
         PrintExceptionContinue(&e, "AppInitRPC()");
         return EXIT_FAILURE;
     } catch (...) {
@@ -252,7 +252,7 @@ int main(int argc, char* argv[])
     try {
         ret = CommandLineRPC(argc, argv);
     }
-    catch (std::exception& e) {
+    catch (const std::exception& e) {
         PrintExceptionContinue(&e, "CommandLineRPC()");
     } catch (...) {
         PrintExceptionContinue(NULL, "CommandLineRPC()");

src/bitcoin-tx.cpp

@@ -586,10 +586,10 @@ static int CommandLineRawTx(int argc, char* argv[])
         OutputTx(tx);
     }
 
-    catch (boost::thread_interrupted) {
+    catch (const boost::thread_interrupted&) {
         throw;
     }
-    catch (std::exception& e) {
+    catch (const std::exception& e) {
         strPrint = string("error: ") + e.what();
         nRet = EXIT_FAILURE;
     }
@@ -612,7 +612,7 @@ int main(int argc, char* argv[])
         if(!AppInitRawTx(argc, argv))
             return EXIT_FAILURE;
     }
-    catch (std::exception& e) {
+    catch (const std::exception& e) {
         PrintExceptionContinue(&e, "AppInitRawTx()");
         return EXIT_FAILURE;
     } catch (...) {
@@ -624,7 +624,7 @@ int main(int argc, char* argv[])
     try {
         ret = CommandLineRawTx(argc, argv);
     }
-    catch (std::exception& e) {
+    catch (const std::exception& e) {
         PrintExceptionContinue(&e, "CommandLineRawTx()");
     } catch (...) {
         PrintExceptionContinue(NULL, "CommandLineRawTx()");

src/bitcoind.cpp

@@ -97,7 +97,7 @@ bool AppInit(int argc, char* argv[])
         try
         {
             ReadConfigFile(mapArgs, mapMultiArgs);
-        } catch(std::exception &e) {
+        } catch (const std::exception& e) {
             fprintf(stderr,"Error reading configuration file: %s\n", e.what());
             return false;
         }
@@ -147,7 +147,7 @@ bool AppInit(int argc, char* argv[])
         detectShutdownThread = new boost::thread(boost::bind(&DetectShutdownThread, &threadGroup));
         fRet = AppInit2(threadGroup);
     }
-    catch (std::exception& e) {
+    catch (const std::exception& e) {
         PrintExceptionContinue(&e, "AppInit()");
     } catch (...) {
         PrintExceptionContinue(NULL, "AppInit()");

src/core_read.cpp

@@ -102,7 +102,7 @@ bool DecodeHexTx(CTransaction& tx, const std::string& strHexTx)
     try {
         ssData >> tx;
     }
-    catch (const std::exception &) {
+    catch (const std::exception&) {
         return false;
     }
 
@@ -119,7 +119,7 @@ bool DecodeHexBlk(CBlock& block, const std::string& strHexBlk)
     try {
         ssBlock >> block;
     }
-    catch (const std::exception &) {
+    catch (const std::exception&) {
         return false;
     }
 

src/init.cpp

@@ -778,7 +778,7 @@ bool AppInit2(boost::thread_group& threadGroup)
             try {
                 boost::filesystem::rename(pathDatabase, pathDatabaseBak);
                 LogPrintf("Moved old %s to %s. Retrying.\n", pathDatabase.string(), pathDatabaseBak.string());
-            } catch(boost::filesystem::filesystem_error &error) {
+            } catch (const boost::filesystem::filesystem_error&) {
                  // failure is ok (well, not really, but it's not worse than what we started with)
             }
 
@@ -931,7 +931,7 @@ bool AppInit2(boost::thread_group& threadGroup)
                 filesystem::create_hard_link(source, dest);
                 LogPrintf("Hardlinked %s -> %s\n", source.string(), dest.string());
                 linked = true;
-            } catch (filesystem::filesystem_error & e) {
+            } catch (const filesystem::filesystem_error& e) {
                 // Note: hardlink creation failing is not a disaster, it just means
                 // blocks will get re-downloaded from peers.
                 LogPrintf("Error hardlinking blk%04u.dat : %s\n", i, e.what());
@@ -1008,7 +1008,7 @@ bool AppInit2(boost::thread_group& threadGroup)
                     strLoadError = _("Corrupted block database detected");
                     break;
                 }
-            } catch(std::exception &e) {
+            } catch (const std::exception& e) {
                 if (fDebug) LogPrintf("%s\n", e.what());
                 strLoadError = _("Error opening block database");
                 break;

src/main.cpp

@@ -1091,7 +1091,7 @@ bool GetTransaction(const uint256 &hash, CTransaction &txOut, uint256 &hashBlock
                     file >> header;
                     fseek(file.Get(), postx.nTxOffset, SEEK_CUR);
                     file >> txOut;
-                } catch (std::exception &e) {
+                } catch (const std::exception& e) {
                     return error("%s : Deserialize or I/O error - %s", __func__, e.what());
                 }
                 hashBlock = header.GetHash();
@@ -1174,7 +1174,7 @@ bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos)
     try {
         filein >> block;
     }
-    catch (std::exception &e) {
+    catch (const std::exception& e) {
         return error("%s : Deserialize or I/O error - %s", __func__, e.what());
     }
 
@@ -2598,7 +2598,7 @@ bool AcceptBlock(CBlock& block, CValidationState& state, CBlockIndex** ppindex,
                 return state.Abort("Failed to write block");
         if (!ReceivedBlockTransactions(block, state, pindex, blockPos))
             return error("AcceptBlock() : ReceivedBlockTransactions failed");
-    } catch(std::runtime_error &e) {
+    } catch (const std::runtime_error& e) {
         return state.Abort(std::string("System error: ") + e.what());
     }
 
@@ -2990,7 +2990,7 @@ bool InitBlockIndex() {
                 return error("LoadBlockIndex() : genesis block cannot be activated");
             // Force a chainstate write so that when we VerifyDB in a moment, it doesn't check stale data
             return FlushStateToDisk(state, FLUSH_STATE_ALWAYS);
-        } catch(std::runtime_error &e) {
+        } catch (const std::runtime_error& e) {
             return error("LoadBlockIndex() : failed to initialize block database: %s", e.what());
         }
     }
@@ -3030,7 +3030,7 @@ bool LoadExternalBlockFile(FILE* fileIn, CDiskBlockPos *dbp)
                 blkdat >> nSize;
                 if (nSize < 80 || nSize > MAX_BLOCK_SIZE)
                     continue;
-            } catch (const std::exception &) {
+            } catch (const std::exception&) {
                 // no valid block header found; don't complain
                 break;
             }
@@ -3090,11 +3090,11 @@ bool LoadExternalBlockFile(FILE* fileIn, CDiskBlockPos *dbp)
                         mapBlocksUnknownParent.erase(it);
                     }
                 }
-            } catch (std::exception &e) {
+            } catch (const std::exception& e) {
                 LogPrintf("%s : Deserialize or I/O error - %s", __func__, e.what());
             }
         }
-    } catch(std::runtime_error &e) {
+    } catch (const std::runtime_error& e) {
         AbortNode(std::string("System error: ") + e.what());
     }
     if (nLoaded > 0)
@@ -4088,7 +4088,7 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
                     ss << ": hash " << hash.ToString();
                 }
                 LogPrint("net", "Reject %s\n", SanitizeString(ss.str()));
-            } catch (std::ios_base::failure& e) {
+            } catch (const std::ios_base::failure&) {
                 // Avoid feedback loops by preventing reject messages from triggering a new reject message.
                 LogPrint("net", "Unparseable reject message received\n");
             }
@@ -4192,7 +4192,7 @@ bool ProcessMessages(CNode* pfrom)
             fRet = ProcessMessage(pfrom, strCommand, vRecv, msg.nTime);
             boost::this_thread::interruption_point();
         }
-        catch (std::ios_base::failure& e)
+        catch (const std::ios_base::failure& e)
         {
             pfrom->PushMessage("reject", strCommand, REJECT_MALFORMED, string("error parsing message"));
             if (strstr(e.what(), "end of data"))
@@ -4210,10 +4210,10 @@ bool ProcessMessages(CNode* pfrom)
                 PrintExceptionContinue(&e, "ProcessMessages()");
             }
         }
-        catch (boost::thread_interrupted) {
+        catch (const boost::thread_interrupted&) {
             throw;
         }
-        catch (std::exception& e) {
+        catch (const std::exception& e) {
             PrintExceptionContinue(&e, "ProcessMessages()");
         } catch (...) {
             PrintExceptionContinue(NULL, "ProcessMessages()");
@@ -4507,7 +4507,7 @@ bool CBlockUndo::ReadFromDisk(const CDiskBlockPos &pos, const uint256 &hashBlock
         filein >> *this;
         filein >> hashChecksum;
     }
-    catch (std::exception &e) {
+    catch (const std::exception& e) {
         return error("%s : Deserialize or I/O error - %s", __func__, e.what());
     }
 

src/miner.cpp

@@ -565,7 +565,7 @@ void static BitcoinMiner(CWallet *pwallet)
             }
         }
     }
-    catch (boost::thread_interrupted)
+    catch (const boost::thread_interrupted&)
     {
         LogPrintf("BitcoinMiner terminated\n");
         throw;

src/net.cpp

@@ -601,7 +601,7 @@ int CNetMessage::readHeader(const char *pch, unsigned int nBytes)
     try {
         hdrbuf >> hdr;
     }
-    catch (const std::exception &) {
+    catch (const std::exception&) {
         return -1;
     }
 
@@ -1068,7 +1068,7 @@ void ThreadMapPort()
                 MilliSleep(20*60*1000); // Refresh every 20 minutes
             }
         }
-        catch (boost::thread_interrupted)
+        catch (const boost::thread_interrupted&)
         {
             r = UPNP_DeletePortMapping(urls.controlURL, data.first.servicetype, port.c_str(), "TCP", 0);
             LogPrintf("UPNP_DeletePortMapping() returned : %d\n", r);
@@ -1854,7 +1854,7 @@ bool CAddrDB::Write(const CAddrMan& addr)
     try {
         fileout << ssPeers;
     }
-    catch (std::exception &e) {
+    catch (const std::exception& e) {
         return error("%s : Serialize or I/O error - %s", __func__, e.what());
     }
     FileCommit(fileout.Get());
@@ -1890,7 +1890,7 @@ bool CAddrDB::Read(CAddrMan& addr)
         filein.read((char *)&vchData[0], dataSize);
         filein >> hashIn;
     }
-    catch (std::exception &e) {
+    catch (const std::exception& e) {
         return error("%s : Deserialize or I/O error - %s", __func__, e.what());
     }
     filein.fclose();
@@ -1914,7 +1914,7 @@ bool CAddrDB::Read(CAddrMan& addr)
         // de-serialize address data into one CAddrMan object
         ssPeers >> addr;
     }
-    catch (std::exception &e) {
+    catch (const std::exception& e) {
         return error("%s : Deserialize or I/O error - %s", __func__, e.what());
     }
 

src/qt/bitcoin.cpp

@@ -173,7 +173,7 @@ private:
     boost::thread_group threadGroup;
 
     /// Pass fatal exception message to UI thread
-    void handleRunawayException(std::exception *e);
+    void handleRunawayException(const std::exception *e);
 };
 
 /** Main Bitcoin application object */
@@ -240,7 +240,7 @@ BitcoinCore::BitcoinCore():
 {
 }
 
-void BitcoinCore::handleRunawayException(std::exception *e)
+void BitcoinCore::handleRunawayException(const std::exception *e)
 {
     PrintExceptionContinue(e, "Runaway exception");
     emit runawayException(QString::fromStdString(strMiscWarning));
@@ -260,7 +260,7 @@ void BitcoinCore::initialize()
             StartDummyRPCThread();
         }
         emit initializeResult(rv);
-    } catch (std::exception& e) {
+    } catch (const std::exception& e) {
         handleRunawayException(&e);
     } catch (...) {
         handleRunawayException(NULL);
@@ -277,7 +277,7 @@ void BitcoinCore::shutdown()
         Shutdown();
         qDebug() << __func__ << ": Shutdown finished";
         emit shutdownResult(1);
-    } catch (std::exception& e) {
+    } catch (const std::exception& e) {
         handleRunawayException(&e);
     } catch (...) {
         handleRunawayException(NULL);
@@ -551,7 +551,7 @@ int main(int argc, char *argv[])
     }
     try {
         ReadConfigFile(mapArgs, mapMultiArgs);
-    } catch(std::exception &e) {
+    } catch (const std::exception& e) {
         QMessageBox::critical(0, QObject::tr("Bitcoin Core"),
                               QObject::tr("Error: Cannot parse configuration file: %1. Only use key=value syntax.").arg(e.what()));
         return false;
@@ -628,7 +628,7 @@ int main(int argc, char *argv[])
         app.exec();
         app.requestShutdown();
         app.exec();
-    } catch (std::exception& e) {
+    } catch (const std::exception& e) {
         PrintExceptionContinue(&e, "Runaway exception");
         app.handleRunawayException(QString::fromStdString(strMiscWarning));
     } catch (...) {

src/qt/intro.cpp

@@ -95,7 +95,7 @@ void FreespaceChecker::check()
                 replyMessage = tr("Path already exists, and is not a directory.");
             }
         }
-    } catch(fs::filesystem_error &e)
+    } catch (const fs::filesystem_error&)
     {
         /* Parent directory does not exist or is not accessible */
         replyStatus = ST_ERROR;
@@ -180,7 +180,7 @@ void Intro::pickDataDirectory()
             try {
                 TryCreateDirectory(GUIUtil::qstringToBoostPath(dataDir));
                 break;
-            } catch(fs::filesystem_error &e) {
+            } catch (const fs::filesystem_error&) {
                 QMessageBox::critical(0, tr("Bitcoin Core"),
                     tr("Error: Specified data directory \"%1\" cannot be created.").arg(dataDir));
                 /* fall through, back to choosing screen */

src/qt/paymentrequestplus.cpp

@@ -181,8 +181,7 @@ bool PaymentRequestPlus::getMerchant(X509_STORE* certStore, QString& merchant) c
         }
         // TODO: detect EV certificates and set merchant = business name instead of unfriendly NID_commonName ?
     }
-    catch (SSLVerifyError& err)
-    {
+    catch (const SSLVerifyError& err) {
         fResult = false;
         qWarning() << "PaymentRequestPlus::getMerchant : SSL error: " << err.what();
     }

src/qt/rpcconsole.cpp

@@ -180,7 +180,7 @@ void RPCExecutor::request(const QString &command)
 
         emit reply(RPCConsole::CMD_REPLY, QString::fromStdString(strPrint));
     }
-    catch (json_spirit::Object& objError)
+    catch (const json_spirit::Object& objError)
     {
         try // Nice formatting for standard-format error
         {
@@ -188,12 +188,12 @@ void RPCExecutor::request(const QString &command)
             std::string message = find_value(objError, "message").get_str();
             emit reply(RPCConsole::CMD_ERROR, QString::fromStdString(message) + " (code " + QString::number(code) + ")");
         }
-        catch(std::runtime_error &) // raised when converting to invalid type, i.e. missing code or message
+        catch (const std::runtime_error&) // raised when converting to invalid type, i.e. missing code or message
         {   // Show raw JSON object
             emit reply(RPCConsole::CMD_ERROR, QString::fromStdString(write_string(json_spirit::Value(objError), false)));
         }
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
         emit reply(RPCConsole::CMD_ERROR, QString("Error: ") + QString::fromStdString(e.what()));
     }

src/rest.cpp

@@ -307,7 +307,7 @@ bool HTTPReq_REST(AcceptedConnection* conn,
                 return uri_prefixes[i].handler(conn, strReq, mapHeaders, fRun);
             }
         }
-    } catch (RestErr& re) {
+    } catch (const RestErr& re) {
         conn->stream() << HTTPReply(re.status, re.message + "\r\n", false, false, "text/plain") << std::flush;
         return false;
     }

src/rpcprotocol.h

@@ -122,8 +122,7 @@ public:
             tcp::resolver::query query(server.c_str(), port.c_str());
             endpoint_iterator = resolver.resolve(query);
 #if BOOST_VERSION >= 104300
-        } catch(boost::system::system_error &e)
-        {
+        } catch (const boost::system::system_error&) {
             // If we at first don't succeed, try blanket lookup (IPv4+IPv6 independent of configured interfaces)
             tcp::resolver::query query(server.c_str(), port.c_str(), resolver_query_base::flags());
             endpoint_iterator = resolver.resolve(query);

src/rpcrawtransaction.cpp

@@ -545,7 +545,7 @@ Value signrawtransaction(const Array& params, bool fHelp)
             ssData >> tx;
             txVariants.push_back(tx);
         }
-        catch (const std::exception &) {
+        catch (const std::exception&) {
             throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed");
         }
     }

src/rpcserver.cpp

@@ -174,7 +174,7 @@ string CRPCTable::help(string strCommand) const
             if (setDone.insert(pfn).second)
                 (*pfn)(params, true);
         }
-        catch (std::exception& e)
+        catch (const std::exception& e)
         {
             // Help text is returned in an exception
             string strHelp = string(e.what());
@@ -631,7 +631,7 @@ void StartRPCThreads()
             try {
                 vEndpoints.push_back(ParseEndpoint(addr, defaultPort));
             }
-            catch(const boost::system::system_error &)
+            catch (const boost::system::system_error&)
             {
                 uiInterface.ThreadSafeMessageBox(
                     strprintf(_("Could not parse -rpcbind value %s as network address"), addr),
@@ -676,7 +676,7 @@ void StartRPCThreads()
             if(bBindAny && bindAddress == asio::ip::address_v6::any() && !v6_only_error)
                 break;
         }
-        catch(boost::system::system_error &e)
+        catch (const boost::system::system_error& e)
         {
             LogPrintf("ERROR: Binding RPC on address %s port %i failed: %s\n", bindAddress.to_string(), endpoint.port(), e.what());
             strerr = strprintf(_("An error occurred while setting up the RPC address %s port %u for listening: %s"), bindAddress.to_string(), endpoint.port(), e.what());
@@ -842,11 +842,11 @@ static Object JSONRPCExecOne(const Value& req)
         Value result = tableRPC.execute(jreq.strMethod, jreq.params);
         rpc_result = JSONRPCReplyObj(result, Value::null, jreq.id);
     }
-    catch (Object& objError)
+    catch (const Object& objError)
     {
         rpc_result = JSONRPCReplyObj(Value::null, objError, jreq.id);
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
         rpc_result = JSONRPCReplyObj(Value::null,
                                      JSONRPCError(RPC_PARSE_ERROR, e.what()), jreq.id);
@@ -922,12 +922,12 @@ static bool HTTPReq_JSONRPC(AcceptedConnection *conn,
 
         conn->stream() << HTTPReplyHeader(HTTP_OK, fRun, strReply.size()) << strReply << std::flush;
     }
-    catch (Object& objError)
+    catch (const Object& objError)
     {
         ErrorReply(conn->stream(), objError, jreq.id);
         return false;
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
         ErrorReply(conn->stream(), JSONRPCError(RPC_PARSE_ERROR, e.what()), jreq.id);
         return false;
@@ -1013,7 +1013,7 @@ json_spirit::Value CRPCTable::execute(const std::string &strMethod, const json_s
         }
         return result;
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
         throw JSONRPCError(RPC_MISC_ERROR, e.what());
     }

src/script/bitcoinconsensus.cpp

@@ -79,7 +79,7 @@ int bitcoinconsensus_verify_script(const unsigned char *scriptPubKey, unsigned i
          set_error(err, bitcoinconsensus_ERR_OK);
 
         return VerifyScript(tx.vin[nIn].scriptSig, CScript(scriptPubKey, scriptPubKey + scriptPubKeyLen), flags, SignatureChecker(tx, nIn), NULL);
-    } catch (std::exception &e) {
+    } catch (const std::exception&) {
         return set_error(err, bitcoinconsensus_ERR_TX_DESERIALIZE); // Error deserializing
     }
 }

src/test/alert_tests.cpp

@@ -92,7 +92,7 @@ struct ReadAlerts
                 alerts.push_back(alert);
             }
         }
-        catch (std::exception) { }
+        catch (const std::exception&) { }
     }
     ~ReadAlerts() { }
 

src/test/rpc_tests.cpp

@@ -39,8 +39,7 @@ Value CallRPC(string args)
         Value result = (*method)(params, false);
         return result;
     }
-    catch (Object& objError)
-    {
+    catch (const Object& objError) {
         throw runtime_error(find_value(objError, "message").get_str());
     }
 }

src/txdb.cpp

@@ -129,7 +129,7 @@ bool CCoinsViewDB::GetStats(CCoinsStats &stats) const {
                 ss << VARINT(0);
             }
             pcursor->Next();
-        } catch (std::exception &e) {
+        } catch (const std::exception& e) {
             return error("%s : Deserialize or I/O error - %s", __func__, e.what());
         }
     }
@@ -218,7 +218,7 @@ bool CBlockTreeDB::LoadBlockIndexGuts()
             } else {
                 break; // if shutdown requested or finished loading block index
             }
-        } catch (std::exception &e) {
+        } catch (const std::exception& e) {
             return error("%s : Deserialize or I/O error - %s", __func__, e.what());
         }
     }

src/txmempool.cpp

@@ -648,7 +648,7 @@ CTxMemPool::WriteFeeEstimates(CAutoFile& fileout) const
         fileout << CLIENT_VERSION; // version that wrote the file
         minerPolicyEstimator->Write(fileout);
     }
-    catch (const std::exception &) {
+    catch (const std::exception&) {
         LogPrintf("CTxMemPool::WriteFeeEstimates() : unable to write policy estimator data (non-fatal)");
         return false;
     }
@@ -667,7 +667,7 @@ CTxMemPool::ReadFeeEstimates(CAutoFile& filein)
         LOCK(cs);
         minerPolicyEstimator->Read(filein, minRelayFee);
     }
-    catch (const std::exception &) {
+    catch (const std::exception&) {
         LogPrintf("CTxMemPool::ReadFeeEstimates() : unable to read policy estimator data (non-fatal)");
         return false;
     }

src/util.cpp

@@ -346,7 +346,7 @@ bool SoftSetBoolArg(const std::string& strArg, bool fValue)
         return SoftSetArg(strArg, std::string("0"));
 }
 
-static std::string FormatException(std::exception* pex, const char* pszThread)
+static std::string FormatException(const std::exception* pex, const char* pszThread)
 {
 #ifdef WIN32
     char pszModule[MAX_PATH] = "";
@@ -362,7 +362,7 @@ static std::string FormatException(std::exception* pex, const char* pszThread)
             "UNKNOWN EXCEPTION       \n%s in %s       \n", pszModule, pszThread);
 }
 
-void PrintExceptionContinue(std::exception* pex, const char* pszThread)
+void PrintExceptionContinue(const std::exception* pex, const char* pszThread)
 {
     std::string message = FormatException(pex, pszThread);
     LogPrintf("\n\n************************\n%s\n", message);
@@ -514,7 +514,7 @@ bool TryCreateDirectory(const boost::filesystem::path& p)
     try
     {
         return boost::filesystem::create_directory(p);
-    } catch (boost::filesystem::filesystem_error) {
+    } catch (const boost::filesystem::filesystem_error&) {
         if (!boost::filesystem::exists(p) || !boost::filesystem::is_directory(p))
             throw;
     }
@@ -721,8 +721,7 @@ void SetupEnvironment()
 #else // boost filesystem v2
             std::locale();                      // Raises runtime error if current locale is invalid
 #endif
-    } catch(std::runtime_error &e)
-    {
+    } catch (const std::runtime_error&) {
         setenv("LC_ALL", "C", 1); // Force C locale
     }
 #endif

src/util.h

@@ -84,7 +84,7 @@ static inline bool error(const char* format)
     return false;
 }
 
-void PrintExceptionContinue(std::exception* pex, const char* pszThread);
+void PrintExceptionContinue(const std::exception *pex, const char* pszThread);
 void ParseParameters(int argc, const char*const argv[]);
 void FileCommit(FILE *fileout);
 bool TruncateFile(FILE *file, unsigned int length);
@@ -186,12 +186,12 @@ template <typename Callable> void LoopForever(const char* name,  Callable func,
             func();
         }
     }
-    catch (boost::thread_interrupted)
+    catch (const boost::thread_interrupted&)
     {
         LogPrintf("%s thread stop\n", name);
         throw;
     }
-    catch (std::exception& e) {
+    catch (const std::exception& e) {
         PrintExceptionContinue(&e, name);
         throw;
     }
@@ -214,12 +214,12 @@ template <typename Callable> void TraceThread(const char* name,  Callable func)
         func();
         LogPrintf("%s thread exit\n", name);
     }
-    catch (boost::thread_interrupted)
+    catch (const boost::thread_interrupted&)
     {
         LogPrintf("%s thread interrupt\n", name);
         throw;
     }
-    catch (std::exception& e) {
+    catch (const std::exception& e) {
         PrintExceptionContinue(&e, name);
         throw;
     }

src/walletdb.cpp

@@ -460,7 +460,7 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
             {
                 ssValue >> hash;
             }
-            catch(...){}
+            catch (...) {}
 
             bool fSkipCheck = false;
 
@@ -664,7 +664,7 @@ DBErrors CWalletDB::LoadWallet(CWallet* pwallet)
         }
         pcursor->close();
     }
-    catch (boost::thread_interrupted) {
+    catch (const boost::thread_interrupted&) {
         throw;
     }
     catch (...) {
@@ -757,7 +757,7 @@ DBErrors CWalletDB::FindWalletTx(CWallet* pwallet, vector<uint256>& vTxHash, vec
         }
         pcursor->close();
     }
-    catch (boost::thread_interrupted) {
+    catch (const boost::thread_interrupted&) {
         throw;
     }
     catch (...) {
@@ -878,7 +878,7 @@ bool BackupWallet(const CWallet& wallet, const string& strDest)
 #endif
                     LogPrintf("copied wallet.dat to %s\n", pathDest.string());
                     return true;
-                } catch(const filesystem::filesystem_error &e) {
+                } catch (const filesystem::filesystem_error& e) {
                     LogPrintf("error copying wallet.dat to %s - %s\n", pathDest.string(), e.what());
                     return false;
                 }