[syserr.syserr] (original) (raw)

19 Diagnostics library [diagnostics]

19.5 System error support [syserr]

19.5.8 Class system_error [syserr.syserr]

19.5.8.1 Overview [syserr.syserr.overview]

The class system_error describes an exception object used to report error conditions that have an associated error code.

Such error conditions typically originate from the operating system or other low-level application program interfaces.

[Note 1:

If an error represents an out-of-memory condition, implementations are encouraged to throw an exception object of type bad_alloc rather than system_error.

— _end note_]

namespace std { class system_error : public runtime_error { public: system_error(error_code ec, const string& what_arg); system_error(error_code ec, const char* what_arg); system_error(error_code ec); system_error(int ev, const error_category& ecat, const string& what_arg); system_error(int ev, const error_category& ecat, const char* what_arg); system_error(int ev, const error_category& ecat);const error_code& code() const noexcept;const char* what() const noexcept override;};}

19.5.8.2 Members [syserr.syserr.members]

system_error(error_code ec, const string& what_arg);

Postconditions: code() == ec and
string_view(what()).find(what_arg.c_str()) != string_view​::​npos.

system_error(error_code ec, const char* what_arg);

Postconditions: code() == ec andstring_view(what()).find(what_arg) != string_view​::​npos.

system_error(error_code ec);

Postconditions: code() == ec.

system_error(int ev, const error_category& ecat, const string& what_arg);

Postconditions: code() == error_code(ev, ecat) and
string_view(what()).find(what_arg.c_str()) != string_view​::​npos.

system_error(int ev, const error_category& ecat, const char* what_arg);

Postconditions: code() == error_code(ev, ecat) and
string_view(what()).find(what_arg) != string_view​::​npos.

system_error(int ev, const error_category& ecat);

Postconditions: code() == error_code(ev, ecat).

const error_code& code() const noexcept;

Returns: ec or error_code(ev, ecat), from the constructor, as appropriate.

const char* what() const noexcept override;

Returns: An ntbs incorporating the arguments supplied in the constructor.

[Note 1:

The returned ntbs might be the contents of what_arg + ": " +code.message().

— _end note_]