std::system_error::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)

Filesystem library (C++17)

Technical Specifications

 

Utilities library

Type support (basic types, RTTI, type traits)

Dynamic memory management

Error handling

Program utilities

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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>=

optional, any and variant (C++17)

optional

any

variant

in_placein_place_typein_place_indexin_place_tin_place_type_tin_place_index_t

Pairs and tuples

pair

tuple (C++11)

apply (C++17)

make_from_tuple (C++17)

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)

Elementary string conversions

to_chars (C++17)

from_chars (C++17)

chars_format (C++17)

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 bad_exception unexpected (until C++17) unexpected_handler (until C++17) get_unexpected (C++11)(until C++17) set_unexpected (until C++17)

Exception categories logic_error invalid_argument domain_error length_error out_of_range runtime_error range_error overflow_error underflow_error tx_exception (TM TS) 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)

 

std::system_error

Member functions

system_error::system_error

system_error::code

system_error::what

 

system_error( std::error_code ec );	(1)	(since C++11)
system_error( std::error_code ec, const std::string& what_arg );	(2)	(since C++11)
system_error( std::error_code ec, const char* what_arg );	(2)	(since C++11)
system_error( int ev, const std::error_category& ecat );	(3)	(since C++11)
system_error( int ev, const std::error_category& ecat,               const std::string& what_arg);	(4)	(since C++11)
system_error( int ev, const std::error_category& ecat,               const char* what_arg);	(4)	(since C++11)

Constructs new system error object.

1) Constructs with error code ec

2) Constructs with error code ec and explanation string what_arg. The string returned by what() is guaranteed to contain what_arg.

3) Constructs with underlying error code ev and associated error category ecat.

4) Constructs with underlying error code ev, associated error category ecat and explanatory string what_arg. The string returned by what() is guaranteed to contain what_arg.

Parameters

ec	-	error code
ev	-	error code in base encoding
ecat	-	the category of error
what_arg	-	explanatory string

Example

Demonstrates how to create a system_error exception from a errno value

Run this code

#include <iostream>
#include <system_error>
 
int main()
{
    try
    {
        throw std::system_error(EDOM, std::generic_category());
    }
    catch (const std::system_error& error)
    {
        std::cout << "Error: " << error.code()
                  << " - " << error.code().message() << '\n';
    }
}

Possible output:

Error: generic:33 - Numerical argument out of domain