Error Handling During File I/O
Sometimes during file operations, errors may also creep in. For instance, a file being opened for reading might not exist. Or a file name used for a new file may already exist.Or an attempt could be made to read past the end-of-file, etc. To check for such errors and to ensure smooth processing, C++ file streams inherit stream-state members from the ios class that store the information on the status of a file that is being currently used. The current state of the I/O system is held in an integer, in which the following flags are encoded :
There are several error handling functions supported by class ios that help you read and process the status recorded in a file stream. Following table lists these error handling functions and their meaning :
These functions may be used in the appropriate places in a program to locate the status of a file stream and thereby take the necessary corrective measures. For example :
. . . ifstream fin ; fin.open ("Master") ; while (! fin.fail ( ) ) { . . . // process the file. } if (fin.eof ( ) ) { . . . // terminate the program. } else if (fin.bad ( ) ) { . . . // report fatal error. } else { fin.clear ( ) ; // clear error - state flags . . . } . . .Read more about this topic: Data File
Famous quotes containing the words error, handling and/or file:
“Custom calls me to’t.
What custom wills, in all things should we do’t,
The dust on antique time would lie unswept,
And mountainous error be too highly heaped
For truth to o’erpeer.”
—William Shakespeare (1564–1616)
“For a novel addressed by a man to men and women of full age; which attempts to deal unaffectedly with the fret and fever, derision and disaster, that may press in the wake of the strongest passion known to humanity; to tell, without a mincing of words, of a deadly war waged between flesh and spirit; and to point the tragedy of unfulfilled aims, I am not aware that there is anything in the handling to which exception can be taken.”
—Thomas Hardy (1840–1928)
“Probably nothing in the experience of the rank and file of workers causes more bitterness and envy than the realization which comes sooner or later to many of them that they are “stuck” and can go no further.”
—Mary Barnett Gilson (1877–?)