Standard Library Exception Categories

Overview

This discusses various standard library exceptions with examples.

Details

The following discusses details about different exception with examples.

logic_error

These are derived from logic_error class defined in std library. 

Name	Description
domain_error	This error is reported by functions that internally call mathematical functions implemented in std library. This exception is thrown when  mathematical functions return inf or NaN.  Note that none of standard library functions throw this error. Example //ret:inf auto ret = pow(0,-1);
future_error	This reports future object related errors with error_code. Example /*prints Exception caught (future_error): Value: 1 (future_errc::future_already_retrieved) Category: future Message: Future already retrieved */ promise<int> prom; try { prom.get_future();         // throws future_error with future_already_retrieved prom.get_future(); } catch (future_error& e) { error_condition cond = e.code().default_error_condition(); cerr << "Exception caught (future_error):" << endl; cerr << "Value: " << cond.value() << endl; cerr << "Category: " << cond.category().name() << endl; cerr << "Message: " << cond.message() << endl; }
invalid_argument	This reports invalid argument related errors. . Example /*prints bitset::_M_copy_from_ptr */ try { //throws error because cannot convert the input string to a number. bitset<128>("ffff").to_ulong(); } catch (invalid_argument& e) { cerr << e.what() << endl; }
length_error	This reports length related errors. e.g., if it's too large. Example /*prints cannot create std::vector larger than max_size() */ try { //throws error because cannot allocate vector of 18446744073709551615 ints. vector<int>(-1); } catch (length_error& e) { cerr << e.what() << endl; }
out_of_range	This reports errors such as  an argument that is out of its valid range. Example /*prints basic_string::append: __pos (which is 1) > this->size() (which is 0) */ try { //throws error because index 1 is past the length of string "". string().append("", 1, 0); } catch (out_of_range& e) { cerr << e.what() << endl; }

misc_error

Note that there is no misc_error class defined in std library. It's given only for notation.

Name	Description
bad_array_new_length	This error is reported when the invalid array size is supplied. Example /*prints std::bad_array_new_length */ try { //throws error because negative length input is supplied. auto n = -1; new int[n] ; } catch (bad_array_new_length & e) { cerr << e.what() << endl; }
bad_alloc	This error is reported when required storage could not be allocated by the new functions. Example /*prints std::bad_alloc */ try { //throws error because it cannot allocate array of 4294967295 ints. new int[numeric_limits<uint>::max()]; } catch (bad_alloc & e) { cerr << e.what() << endl; }
bad_cast	This error is reported by dynamic_cast when it fails the run-time check performed on references to polymorphic class types. Example /*prints std::bad_cast */ try { //throws error because exception class is not derived from bad_cast class. //It's other way round. dynamic_cast<bad_cast&>( exception()); } catch (bad_cast & e) { cerr << e.what() << endl; }
bad_typeid	This error is reported by typeid when applied on a pointer to a polymorphic type which has a null pointer value. Example /*prints std::bad_typeid */ try { //throws error because nullptr is passed as input. typeid(* ( (exception*)nullptr) ).name(); } catch (bad_typeid & e) { cerr << e.what() << endl; }
bad_exception	is reported by unexpected_handler, if the bad_exception is declared in throw specification of the function declaration, when such a function throws wrong type.  Example /*prints unexpected handler called caught bad_exception:std::bad_exception */ void myunexpected () { cerr << "unexpected handler called" << endl; throw; } void myfunction () throw (int,bad_exception) { // throws char (not in exception-specification) throw 'x'; } set_unexpected (myunexpected); try { myfunction(); } catch (int) { cerr << "caught int" << endl; } catch (bad_exception e) { cerr << "caught bad_exception:" << e.what() << endl; } catch (...) { cerr << "caught some other exception" << endl; }

runtime_error

underlying os or file system related exceptions such as system_error such as file does not exist. These are derived from runtime_error class defined in std library.

Name	Description
range_error	This error is reported  when the result of a computation cannot be represented by the destination type. Example /*prints wstring_convert::from_bytes */ try { //throws error because char range passed as input should be within 0x00 - 0x80. wstring_convert<codecvt_utf8<char32_t>,char32_t>().from_bytes(string("\xff")); } catch (range_error& e) { cerr << e.what() << endl; }
overflow_error	This is reported for arithmetic overflow errors. Example /*prints w_Base_bitset::_M_do_to_ulong */ try { bitset<128> b; b[64] = 1; //throws error because number is too large b.to_ulong(); } catch (overflow_error& e) { cerr << e.what() << endl; }
underflow_error	This is reported  for arithmetic underflow errors. Standard library functions don't throw this error.
system_error	This is reported for  underlying os related exceptions with error_code.  e.g., thread().detach() throws this exception with errc::invalid_argument since  thread object does not have a handler. Example /*prints Exception caught (system_error): Value: 22 (errc::invalid_argument) Category: generic Message: Invalid argument */ try { //throws error because thread is invalid thread().detach(); } catch (system_error& e) { error_condition cond = e.code().default_error_condition(); cerr << "Exception caught (system_error):" << endl; cerr << "Value: " << cond.value() << endl; cerr << "Category: " << cond.category().name() << endl; cerr << "Message: " << cond.message() << endl; }
ios_base::failure	This is reported for  underlying file system related exceptions with error_code.   Example /*prints Exception caught (ios_base::failure): Value: 1 (io_errc::stream) Category: iostream Message: iostream error */ promise<int> prom; try { //throws error because file name is invalid ifstream("doesn't exist").exceptions(ifstream::failbit); } catch (ios_base::failure& e) { error_condition cond = e.code().default_error_condition(); cerr << "Exception caught (ios_base::failure):" << endl; cerr << "Value: " << cond.value() << endl; cerr << "Category: " << cond.category().name() << endl; cerr << "Message: " << cond.message() << endl; }