std::system_error

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Technical Specifications

 

Utilities library

Type support (basic types, RTTI, type traits)

Dynamic memory management

Error handling

Program utilities

Variadic functions

Date and time

Function objects

initializer_list (C++11)

bitset

hash (C++11)

Relational operators

rel_ops::operator!=rel_ops::operator>rel_ops::operator<=rel_ops::operator>=

Pairs and tuples

pair

tuple (C++11)

piecewise_construct_t (C++11)

piecewise_construct (C++11)

integer_sequence (C++14)

Swap, forward and move

swap

exchange (C++14)

forward (C++11)

move (C++11)

move_if_noexcept (C++11)

Type operations

declval (C++11)

as_const (C++17)

 

Error handling

Exception handling

exception

uncaught_exceptionuncaught_exceptions (C++17)

exception_ptr (C++11)

make_exception_ptr (C++11)

current_exception (C++11)

rethrow_exception (C++11)

nested_exception (C++11)

throw_with_nested (C++11)

rethrow_if_nested (C++11)

Exception handling failures

terminate

terminate_handler

get_terminate (C++11)

set_terminate

unexpected (deprecated)

bad_exception

unexpected_handler (deprecated)

get_unexpected (C++11)(deprecated)

set_unexpected (deprecated)

Exception categories

logic_error

invalid_argument

domain_error

length_error

out_of_range

runtime_error

range_error

overflow_error

underflow_error

Error codes

Error codes

errno

Assertions

assert

system_error facility

error_category (C++11)

generic_category (C++11)

system_category (C++11)

error_condition (C++11)

errc (C++11)

error_code (C++11)

system_error (C++11)

 

Defined in header <system_error>
class system_error;		(since C++11)

std::system_error is the type of the exception thrown by various library functions (typically the functions that interface with the OS facilities, e.g. the constructor of std::thread) when the exception has an associated std::error_code, which may be reported.

Inheritance diagram

Member functions

(constructor)	constructs the system_error object (public member function)
code	returns error code (public member function)
what [virtual]	returns explanatory string (virtual public member function)

Inherited from std::exception

Member functions

(destructor) [virtual]	destructs the exception object (virtual public member function of std::exception)
what [virtual]	returns an explanatory string (virtual public member function of std::exception)

Example

Run this code

#include <thread>
#include <iostream>
#include <system_error>
 
int main()
{
    try {
        std::thread().detach(); // attempt to detach a non-thread
    } catch(const std::system_error& e) {
        std::cout << "Caught system_error with code " << e.code() 
                  << " meaning " << e.what() << '\n';
    }
}

Output:

Caught system_error with code generic:22 meaning Invalid argument