30 Input/output library [input.output]

30.5 Iostreams base classes [iostreams.base]

30.5.3 Class ios_­base [ios.base]

30.5.3.1 Types [ios.types]

30.5.3.1.1 Class ios_­base​::​failure [ios::failure]

namespace std {
  class ios_base::failure : public system_error {
  public:
    explicit failure(const string& msg, const error_code& ec = io_errc::stream);
    explicit failure(const char* msg, const error_code& ec = io_errc::stream);
  };
}
1
#
An implementation is permitted to define ios_­base​::​failure as a synonym for a class with equivalent functionality to class ios_­base​::​failure shown in this subclause.
[ Note
:
When ios_­base​::​failure is a synonym for another type it shall provide a nested type failure, to emulate the injected class name.
— end note
 ]
The class failure defines the base class for the types of all objects thrown as exceptions, by functions in the iostreams library, to report errors detected during stream buffer operations.
2
#
When throwing ios_­base​::​failure exceptions, implementations should provide values of ec that identify the specific reason for the failure.
[ Note
:
Errors arising from the operating system would typically be reported as system_­category() errors with an error value of the error number reported by the operating system.
Errors arising from within the stream library would typically be reported as error_­code(io_­errc​::​stream, iostream_­category()).
— end note
 ]
explicit failure(const string& msg, const error_code& ec = io_errc::stream);
3
#
Effects: Constructs an object of class failure by constructing the base class with msg and ec.
explicit failure(const char* msg, const error_code& ec = io_errc::stream);
4
#
Effects: Constructs an object of class failure by constructing the base class with msg and ec.