Stream Error Functions in C

Question: What are Stream Error Functions in C Language?

Answer: We have functions in ANSI C specification which are used to determine the state of a stream. These are prototyped below,

    int feof(FILE *stream);
    int ferror(FILE *stream);
    void clearerr(FILE *stream);

‘feof()’ returns TRUE if stream is currently at end of file. Well! We have already seen that we can change current position in the file using fseek(), rewind() or fsetpos() functions. For ex.

To set to the beginning in a given stream,

    stream = fopen("file", "r");
    rewind(stream);

or we can use

Note: Join free Sanfoundry classes at Telegram or Youtube

    fseek(stream, 0, SEEK_SET);

‘ferror()’ reports on error state of stream and returns TRUE if any read/write errors have occurred.

Take C Programming Tests Now!

/* ferror.c */
#include <stdio.h>
#include <stdlib.h>
#define SIZE 10
 
int main(void)
{
    FILE *stream;
    char buffer[SIZE];
 
    stream = fopen("hello.txt", "r");
    if (stream == NULL) {
        perror("File Open");
        exit(EXIT_FAILURE);
    }
 
    /* read from the stream into buffer */
    fgets(buffer, SIZE, stream);
 
    /* check if there were any read/erite errors */
    if (ferror(stream))
        printf("Read/ Write Error.\n");
 
    return 0;
}