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ferror() function in C language with Example

Here, we are going to learn about the ferror() function of library header stdio.h in C language with its syntax, example.
Submitted by Souvik Saha, on January 06, 2019

ferror() function in C

Prototype:

    int ferror(FILE *filename);

Parameters:

    FILE *filename

Return type: int(0 or 1)

Use of function:

If in the last file operation there is some error introduced in that file, by the ferror() function we identify there is some error in that file during the last operation. The prototype of ferror() function is int ferror(FILE* filename);

But only detects the last operational error of the file because every time the error flag of the file is set.

ferror() example in C

#include <stdio.h>
#include <stdlib.h>

int main()
{
    FILE* f;
    char str[100];

    //Check the existence of that file
    if ((f = fopen("includehelp.txt", "r")) == NULL) {
        printf("Cannot open the file...");
        //if not exist program is terminated
        exit(1);
    }

    // Check if here is some error in the file
    if (ferror(f))
        printf("Error to read the file\n");
    else
        printf("No error in reading\n");

    printf("File content is--\n");
    //print the strings until EOF is encountered
    while (!feof(f)) {
        fgets(str, 100, f);
        //print the string
        printf("%s", str);
    }

    //close the opened file
    fclose(f);

    return 0;
}

Output

C stdio.h Library Functions Programs »

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