|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | NOTES | CAVEATS | SEE ALSO | COLOPHON |
|
|
|
ferror(3) Library Functions Manual ferror(3)
clearerr, feof, ferror - check and reset stream status
Standard C library (libc, -lc)
#include <stdio.h>
void clearerr(FILE *stream);
int feof(FILE *stream);
int ferror(FILE *stream);
The function clearerr() clears the end-of-file and error
indicators for the stream pointed to by stream.
The function feof() tests the end-of-file indicator for the stream
pointed to by stream, returning nonzero if it is set. The end-of-
file indicator can be cleared only by the function clearerr().
The function ferror() tests the error indicator for the stream
pointed to by stream, returning nonzero if it is set. The error
indicator can be reset only by the clearerr() function.
For nonlocking counterparts, see unlocked_stdio(3).
The feof() function returns nonzero if the end-of-file indicator
is set for stream; otherwise, it returns zero.
The ferror() function returns nonzero if the error indicator is
set for stream; otherwise, it returns zero.
These functions should not fail and do not set errno.
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│ clearerr(), feof(), ferror() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘
C11, POSIX.1-2008.
C89, POSIX.1-2001.
POSIX.1-2008 specifies that these functions shall not change the
value of errno if stream is valid.
Normally, programs should read the return value of an input
function, such as fgetc(3), before using functions of the feof(3)
family. Only when the function returned the sentinel value EOF it
makes sense to distinguish between the end of a file or an error
with feof(3) or ferror(3).
open(2), fdopen(3), fileno(3), stdio(3), unlocked_stdio(3)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-05-17 ferror(3)
Pages that refer to this page: EOF(3const), ferror(3), fgetc(3), fread(3), fseek(3), gets(3), getw(3), puts(3), scanf(3), stdio(3)
|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|