ferror() — Test for Read/Write Errors
Format
#include <stdio.h>
int ferror(FILE *stream);Language Level
ANSI
Threadsafe
Yes
Description
The ferror() function
tests for an error in reading from or writing to the given stream.
If an error occurs, the error indicator for the stream remains
set until you close stream, call the rewind() function,
or call the clearerr() function.
Return Value
The ferror() function
returns a nonzero value to indicate an error on the given stream.
A return value of 0 means that no error has occurred.
Example
This example puts data out to a
stream, and then checks that a write error has not occurred.
#include <stdio.h>
int main(void)
{
FILE *stream;
char *string = "Important information";
stream = fopen("mylib/myfile","w");
fprintf(stream, "%s\n", string);
if (ferror(stream))
{
printf("write error\n");
clearerr(stream);
}
if (fclose(stream))
perror("fclose error");
}