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Diffstat (limited to 'man3/ferror.3')
-rw-r--r-- | man3/ferror.3 | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/man3/ferror.3 b/man3/ferror.3 new file mode 100644 index 0000000..68791f1 --- /dev/null +++ b/man3/ferror.3 @@ -0,0 +1,119 @@ +'\" t +.\" Copyright (c) 1990, 1991 The Regents of the University of California. +.\" and Copyright (C) 2021 Michael Kerrisk <mtk.manpages@gmail.com> +.\" All rights reserved. +.\" +.\" This code is derived from software contributed to Berkeley by +.\" Chris Torek and the American National Standards Committee X3, +.\" on Information Processing Systems. +.\" +.\" SPDX-License-Identifier: BSD-4-Clause-UC +.\" +.\" @(#)ferror.3 6.8 (Berkeley) 6/29/91 +.\" +.\" +.\" Converted for Linux, Mon Nov 29 14:24:40 1993, faith@cs.unc.edu +.\" +.TH ferror 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +clearerr, feof, ferror \- check and reset stream status +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <stdio.h> +.PP +.BI "void clearerr(FILE *" stream ); +.BI "int feof(FILE *" stream ); +.BI "int ferror(FILE *" stream ); +.fi +.SH DESCRIPTION +The function +.BR clearerr () +clears the end-of-file and error indicators for the stream pointed to by +.IR stream . +.PP +The function +.BR feof () +tests the end-of-file indicator for the stream pointed to by +.IR stream , +returning nonzero if it is set. +The end-of-file indicator can be cleared only by the function +.BR clearerr (). +.PP +The function +.BR ferror () +tests the error indicator for the stream pointed to by +.IR stream , +returning nonzero if it is set. +The error indicator can be reset only by the +.BR clearerr () +function. +.PP +For nonlocking counterparts, see +.BR unlocked_stdio (3). +.SH RETURN VALUE +The +.BR feof () +function returns nonzero if the end-of-file indicator is set for +.IR stream ; +otherwise, it returns zero. +.PP +The +.BR ferror () +function returns nonzero if the error indicator is set for +.IR stream ; +otherwise, it returns zero. +.SH ERRORS +These functions should not fail and do not set +.IR errno . +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR clearerr (), +.BR feof (), +.BR ferror () +T} Thread safety MT-Safe +.TE +.sp 1 +.SH STANDARDS +C11, POSIX.1-2008. +.SH HISTORY +C89, POSIX.1-2001. +.SH NOTES +POSIX.1-2008 specifies +.\"https://www.austingroupbugs.net/view.php?id=401 +that these functions shall not change the value of +.I errno +if +.I stream +is valid. +.SH CAVEATS +Normally, +programs should read the return value of an input function, +such as +.BR fgetc (3), +before using functions of the +.BR feof (3) +family. +Only when the function returned the sentinel value +.B EOF +it makes sense to distinguish between the end of a file or an error with +.BR feof (3) +or +.BR ferror (3). +.SH SEE ALSO +.BR open (2), +.BR fdopen (3), +.BR fileno (3), +.BR stdio (3), +.BR unlocked_stdio (3) |