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ferror(3) [freebsd man page]

FERROR(3)						   BSD Library Functions Manual 						 FERROR(3)

NAME
clearerr, clearerr_unlocked, feof, feof_unlocked, ferror, ferror_unlocked, fileno, fileno_unlocked -- check and reset stream status LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <stdio.h> void clearerr(FILE *stream); void clearerr_unlocked(FILE *stream); int feof(FILE *stream); int feof_unlocked(FILE *stream); int ferror(FILE *stream); int ferror_unlocked(FILE *stream); int fileno(FILE *stream); int fileno_unlocked(FILE *stream); DESCRIPTION
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 non-zero if it is set. The end-of-file indicator may be cleared by explicitly calling clearerr(), or as a side-effect of other operations, e.g. fseek(). The function ferror() tests the error indicator for the stream pointed to by stream, returning non-zero if it is set. The function fileno() examines the argument stream and returns its integer descriptor. The clearerr_unlocked(), feof_unlocked(), ferror_unlocked(), and fileno_unlocked() functions are equivalent to clearerr(), feof(), ferror(), and fileno() respectively, except that the caller is responsible for locking the stream with flockfile(3) before calling them. These func- tions may be used to avoid the overhead of locking the stream and to prevent races when multiple threads are operating on the same stream. ERRORS
These functions should not fail and do not set the external variable errno. SEE ALSO
open(2), fdopen(3), flockfile(3), stdio(3) STANDARDS
The functions clearerr(), feof(), and ferror() conform to ISO/IEC 9899:1990 (``ISO C90''). BSD
January 28, 2009 BSD

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FERROR(3)                                                    Linux Programmer's Manual                                                   FERROR(3)

NAME
clearerr, feof, ferror, fileno - check and reset stream status SYNOPSIS
#include <stdio.h> void clearerr(FILE *stream); int feof(FILE *stream); int ferror(FILE *stream); int fileno(FILE *stream); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): fileno(): _POSIX_C_SOURCE DESCRIPTION
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. The function fileno() examines the argument stream and returns its integer file descriptor. For nonlocking counterparts, see unlocked_stdio(3). ERRORS
These functions should not fail and do not set the external variable errno. (However, in case fileno() detects that its argument is not a valid stream, it must return -1 and set errno to EBADF.) ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +--------------------+---------------+---------+ |Interface | Attribute | Value | +--------------------+---------------+---------+ |clearerr(), feof(), | Thread safety | MT-Safe | |ferror(), fileno() | | | +--------------------+---------------+---------+ CONFORMING TO
The functions clearerr(), feof(), and ferror() conform to C89, C99, POSIX.1-2001, and POSIX.1-2008. The function fileno() conforms to POSIX.1-2001 and POSIX.1-2008. SEE ALSO
open(2), fdopen(3), stdio(3), unlocked_stdio(3) COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. 2017-09-15 FERROR(3)

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