ferror

 

C

Language

Standard Library

Type support

Dynamic memory management

Error handling

Program utilities

Date and time utilities

Strings library

Algorithms

Numerics

Input/output support

Localization support

Thread support (C11)

Atomic operations (C11)

 

File input/output

Functions
File access
fopen freopen fclose fflush	fwide setbuf setvbuf
Direct input/output
fread
fwrite
Unformatted input/output
fgetc fgets fputc fputs getchar gets putchar puts ungetc	fgetwc fgetws fputwc fputws getwchar putwchar ungetwc
Formatted input/output
scanffscanfsscanf vscanfvfscanfvsscanf (C99)(C99)(C99) printffprintfsprintfsnprintf (C99) vprintfvfprintfvsprintfvsnprintf (C99)	wscanffwscanfswscanf vwscanfvfwscanfvswscanf (C99)(C99)(C99) wprintffwprintfswprintf vwprintfvfwprintfvswprintf
File positioning
ftell
fgetpos
fseek
fsetpos
rewind
Error handling
clearerr
feof
ferror
perror
Operations on files
remove
rename
tmpfile
tmpnam

 

Defined in header <stdio.h>
int ferror( FILE *stream );

Checks the given stream for errors.

Parameters

stream

-

the file stream to check

Return value

nonzero value if the file stream has errors occurred, ​0​ otherwise

Example

ferror used in error checking

Run this code

#include <stdio.h>
#include <stdlib.h>
 
int main(void)
{
    FILE* tmpf = tmpfile();
    fputs("abcde\n", tmpf); 
    rewind(tmpf);
 
    int ch;
    while ((ch=fgetc(tmpf)) != EOF)   /* read/print characters including newline */
          printf("%c", ch);
 
    /* Test reason for reaching EOF. */
    if (feof(tmpf))          /* if failure caused by end-of-file condition */
       puts("End of file reached successfully");
    else if (ferror(tmpf))   /* if failure caused by some other error      */
         {
            perror("fgetc()");
            fprintf(stderr,"fgetc() failed in file %s at line # %d\n", __FILE__,__LINE__-9);
            exit(EXIT_FAILURE);
         }
 
    return EXIT_SUCCESS;
}

Output:

abcde
End of file reached successfully

See also

clearerr	clears errors (function)
feof	checks for the end-of-file (function)
perror	displays a character string corresponding of the current error to stderr (function)
C++ documentation for ferror