.\" .\" Sun Microsystems, Inc. gratefully acknowledges The Open Group for .\" permission to reproduce portions of its copyrighted documentation. .\" Original documentation from The Open Group can be obtained online at .\" http://www.opengroup.org/bookstore/. .\" .\" The Institute of Electrical and Electronics Engineers and The Open .\" Group, have given us permission to reprint portions of their .\" documentation. .\" .\" In the following statement, the phrase ``this text'' refers to portions .\" of the system documentation. .\" .\" Portions of this text are reprinted and reproduced in electronic form .\" in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition, .\" Standard for Information Technology -- Portable Operating System .\" Interface (POSIX), The Open Group Base Specifications Issue 6, .\" Copyright (C) 2001-2004 by the Institute of Electrical and Electronics .\" Engineers, Inc and The Open Group. In the event of any discrepancy .\" between these versions and the original IEEE and The Open Group .\" Standard, the original IEEE and The Open Group Standard is the referee .\" document. The original Standard can be obtained online at .\" http://www.opengroup.org/unix/online.html. .\" .\" This notice shall appear on any product containing this material. .\" .\" The contents of this file are subject to the terms of the .\" Common Development and Distribution License (the "License"). .\" You may not use this file except in compliance with the License. .\" .\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE .\" or http://www.opensolaris.org/os/licensing. .\" See the License for the specific language governing permissions .\" and limitations under the License. .\" .\" When distributing Covered Code, include this CDDL HEADER in each .\" file and include the License file at usr/src/OPENSOLARIS.LICENSE. .\" If applicable, add the following below this CDDL HEADER, with the .\" fields enclosed by brackets "[]" replaced with your own identifying .\" information: Portions Copyright [yyyy] [name of copyright owner] .\" .\" .\" Copyright (c) 1992, X/Open Company Limited. All Rights Reserved. .\" Portions Copyright (c) 2002, Sun Microsystems, Inc. All Rights Reserved. .\" .TH FFLUSH 3C "March 25, 2020" .SH NAME fflush \- flush a stream .SH SYNOPSIS .nf #include \fBint\fR \fBfflush\fR(\fBFILE *\fR\fIstream\fR); .fi .SH DESCRIPTION If \fIstream\fR points to an output stream or an update stream in which the most recent operation was not input, \fBfflush()\fR causes any unwritten data for that stream to be written to the file, and the \fBst_ctime\fR and \fBst_mtime\fR fields of the underlying file are marked for update. .sp .LP If \fIstream\fR points to an input stream or an update stream into which the most recent operation was input, that stream is flushed if it is seekable and is not already at end-of-file. Flushing an input stream discards any buffered input and adjusts the file pointer such that the next input operation accesses the byte after the last one read. A stream is seekable if the underlying file is not a pipe, FIFO, socket, or TTY device. .sp .LP If \fIstream\fR is a null pointer, \fBfflush()\fR performs this flushing action on all streams for which the behavior is defined above. .sp .LP An input stream, seekable or non-seekable, can be flushed by explicitly calling \fBfflush()\fR with a non-null argument specifying that stream. .SH RETURN VALUES Upon successful completion, \fBfflush()\fR returns \fB0\fR. Otherwise, it returns \fBEOF\fR and sets \fBerrno\fR to indicate the error. .SH ERRORS The \fBfflush()\fR function will fail if: .sp .ne 2 .na \fB\fBEAGAIN\fR\fR .ad .RS 10n The \fBO_NONBLOCK\fR flag is set for the file descriptor underlying \fIstream\fR and the process would be delayed in the write operation. .RE .sp .ne 2 .na \fB\fBEBADF\fR\fR .ad .RS 10n The file descriptor underlying \fIstream\fR is not valid. .RE .sp .ne 2 .na \fB\fBEFBIG\fR\fR .ad .RS 10n An attempt was made to write a file that exceeds the maximum file size or the process's file size limit; or the file is a regular file and an attempt was made to write at or beyond the offset maximum associated with the corresponding stream. .RE .sp .ne 2 .na \fB\fBEINTR\fR\fR .ad .RS 10n The \fBfflush()\fR function was interrupted by a signal. .RE .sp .ne 2 .na \fB\fBEIO\fR\fR .ad .RS 10n The process is a member of a background process group attempting to write to its controlling terminal, \fBTOSTOP\fR is set, the process is neither ignoring nor blocking \fBSIGTTOU\fR, and the process group of the process is orphaned. \fIstream\fR was created by \fBopen_wmemstream\fR(3C) and a wide-character or byte sequence buffered is invalid in the current locale. .RE .sp .ne 2 .na \fB\fBENOSPC\fR\fR .ad .RS 10n There was no free space remaining on the device containing the file. .RE .sp .ne 2 .na \fB\fBEPIPE\fR\fR .ad .RS 10n An attempt is made to write to a pipe or \fBFIFO\fR that is not open for reading by any process. A \fBSIGPIPE\fR signal will also be sent to the calling process. .RE .sp .LP The \fBfflush()\fR function may fail if: .sp .ne 2 .na \fB\fBENXIO\fR\fR .ad .RS 9n A request was made of a non-existent device, or the request was beyond the limits of the device. .RE .SH ATTRIBUTES See \fBattributes\fR(5) for descriptions of the following attributes: .sp .sp .TS box; c | c l | l . ATTRIBUTE TYPE ATTRIBUTE VALUE _ Interface Stability Standard _ MT-Level MT-Safe .TE .SH SEE ALSO \fBgetrlimit\fR(2), \fBulimit\fR(2), \fBattributes\fR(5), \fBstandards\fR(5)