HP 3000 Manuals HP 3000 Manuals
ferror
Tests whether the error indicator for a stream has been set.
Syntax
#include <stdio.h>
int ferror (FILE *stream);
Parameters
stream A pointer to a file to be tested.
Return Values
0 Error indicator has not been set.
!=0 Error indicator has been set.
Description
The ferror function is intended to clarify ambiguous return values from
standard I/O functions.
The ferror function returns a nonzero value if the error indicator was
set on the specified stream. It does not reset the indicator. You need
to use the clearerr function to reset it.
Because I/O functions return EOF for end-of-file and error conditions,
you can use ferror() and feof() to distinguish between them. Also, some
systems support I/O functions that take integer data instead of
characters. For these functions, you need to use ferror() and feof() to
differentiate between valid data and the EOF flag.
See Also
fopen(), feof(), ANSI C 4.9.10.3, POSIX.1 8.1