public member class
<ios> <iostream>
Base class for stream exceptions
This embedded class inherits from 
exception and serves as the base class for the 
exceptions thrown by the elements of the standard input/output library.
It is defined as:
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 | class ios_base::failure : public exception {
public:
  explicit failure (const string& msg);
  virtual ~failure();
  virtual const char* what() const throw();
}
 | 
Member 
what returns the 
msg with which the exception is constructed.
The specific value for 
msg is entirely implementation-defined.
This embedded class inherits from 
system_error and serves as the base class for the 
exceptions thrown by the elements of the standard input/output library.
It is defined as:
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 | 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);
}
 | 
These errors are typically categorized either in the 
iostream_category (if they relate to the operations of the library) or in the 
system_category (if the error arises from the system). Although the specifics are implementation-defined.
The library implementation may use values of type 
io_errc to portably identify 
error conditions of the 
iostream_category.
 
 
Member functions
- what
- Get string identifying exception ( public member function
)
 
- code 
- Get error code (public member function
)
- what 
- Get message associated to exception (public member function
)