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:
“Never miss an opportunity to allow a child to do something she can and wants to on her own. Sometimes we’re in too much of a rush—and she might spill something, or do it wrong. But whenever possible she needs to learn, error by error, lesson by lesson, to do better. And the more she is able to learn by herself the more she gets the message that she’s a kid who can.”
—Polly Berrien Berends (20th century)
“That a good fit between parental handling and child temperament is vital to help children adapt to the imperatives of their society is a crucial concept that can be applied to other cultures.”
—Stella Chess (20th century)
“I have been a soreheaded occupant of a file drawer labeled “Science Fiction” ... and I would like out, particularly since so many serious critics regularly mistake the drawer for a urinal.”
—Kurt Vonnegut, Jr. (b. 1922)