use const references in catch blocks

src/common/command_line.h

@@ -168,7 +168,7 @@ namespace command_line
     {
       return parser();
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
       std::cerr << "Failed to parse arguments: " << e.what() << std::endl;
       std::cerr << desc << std::endl;

src/simplewallet/simplewallet.cpp

@@ -1327,7 +1327,7 @@ std::string simple_wallet::get_mnemonic_language()
         fail_msg_writer() << tr("invalid language choice passed. Please try again.\n");
       }
     }
-    catch (std::exception &e)
+    catch (const std::exception &e)
     {
       fail_msg_writer() << tr("invalid language choice passed. Please try again.\n");
     }
@@ -4053,7 +4053,7 @@ bool simple_wallet::export_key_images(const std::vector<std::string> &args)
       return true;
     }
   }
-  catch (std::exception &e)
+  catch (const std::exception &e)
   {
     LOG_ERROR("Error exporting key images: " << e.what());
     fail_msg_writer() << "Error exporting key images: " << e.what();

src/wallet/api/pending_transaction.cpp

@@ -124,7 +124,7 @@ bool PendingTransactionImpl::commit(const std::string &filename, bool overwrite)
         m_errorString = writer.str();
         if (!reason.empty())
           m_errorString  += string(tr(". Reason: ")) + reason;
-    } catch (std::exception &e) {
+    } catch (const std::exception &e) {
         m_errorString = string(tr("Unknown exception: ")) + e.what();
         m_status = Status_Error;
     } catch (...) {

src/wallet/api/wallet.cpp

@@ -833,7 +833,7 @@ bool WalletImpl::exportKeyImages(const string &filename)
       return false;
     }
   }
-  catch (std::exception &e)
+  catch (const std::exception &e)
   {
     LOG_ERROR("Error exporting key images: " << e.what());
     m_errorString = e.what();

src/wallet/wallet_rpc_server.cpp

@@ -252,7 +252,7 @@ namespace tools
       res.balance = m_wallet.balance();
       res.unlocked_balance = m_wallet.unlocked_balance();
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
       er.code = WALLET_RPC_ERROR_CODE_UNKNOWN_ERROR;
       er.message = e.what();
@@ -267,7 +267,7 @@ namespace tools
     {
       res.address = m_wallet.get_account().get_public_address_str(m_wallet.testnet());
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
       er.code = WALLET_RPC_ERROR_CODE_UNKNOWN_ERROR;
       er.message = e.what();
@@ -282,7 +282,7 @@ namespace tools
     {
       res.height = m_wallet.get_blockchain_current_height();
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
       er.code = WALLET_RPC_ERROR_CODE_UNKNOWN_ERROR;
       er.message = e.what();
@@ -636,7 +636,7 @@ namespace tools
       res.payment_id = epee::string_tools::pod_to_hex(payment_id);
       return true;
     }
-    catch (std::exception &e)
+    catch (const std::exception &e)
     {
       er.code = WALLET_RPC_ERROR_CODE_UNKNOWN_ERROR;
       er.message = e.what();
@@ -669,7 +669,7 @@ namespace tools
       res.payment_id = epee::string_tools::pod_to_hex(payment_id);
       return true;
     }
-    catch (std::exception &e)
+    catch (const std::exception &e)
     {
       er.code = WALLET_RPC_ERROR_CODE_UNKNOWN_ERROR;
       er.message = e.what();
@@ -691,7 +691,7 @@ namespace tools
     {
       m_wallet.store();
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
       er.code = WALLET_RPC_ERROR_CODE_UNKNOWN_ERROR;
       er.message = e.what();
@@ -911,7 +911,7 @@ namespace tools
     {
       m_wallet.rescan_blockchain();
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
       er.code = WALLET_RPC_ERROR_CODE_UNKNOWN_ERROR;
       er.message = e.what();
@@ -970,7 +970,7 @@ namespace tools
       m_wallet.store();
       m_stop.store(true, std::memory_order_relaxed);
     }
-    catch (std::exception& e)
+    catch (const std::exception& e)
     {
       er.code = WALLET_RPC_ERROR_CODE_UNKNOWN_ERROR;
       er.message = e.what();