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| -rw-r--r-- | man2/bdflush.2 | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/man2/bdflush.2 b/man2/bdflush.2 new file mode 100644 index 0000000..d97949e --- /dev/null +++ b/man2/bdflush.2 @@ -0,0 +1,103 @@ +.\" Copyright (c) 1995 Michael Chastain (mec@shell.portal.com), 15 April 1995. +.\" +.\" SPDX-License-Identifier: GPL-2.0-or-later +.\" +.\" Modified 1997-01-31 by Eric S. Raymond <esr@thyrsus.com> +.\" Modified 2004-06-17 by Michael Kerrisk <mtk.manpages@gmail.com> +.\" +.TH bdflush 2 2023-03-30 "Linux man-pages 6.05.01" +.SH NAME +bdflush \- start, flush, or tune buffer-dirty-flush daemon +.SH SYNOPSIS +.nf +.B #include <sys/kdaemon.h> +.PP +.BI "[[deprecated]] int bdflush(int " func ", long *" address ); +.BI "[[deprecated]] int bdflush(int " func ", long " data ); +.fi +.SH DESCRIPTION +.IR Note : +Since Linux 2.6, +.\" As noted in changes in the 2.5.12 source +this system call is deprecated and does nothing. +It is likely to disappear altogether in a future kernel release. +Nowadays, the task performed by +.BR bdflush () +is handled by the kernel +.I pdflush +thread. +.PP +.BR bdflush () +starts, flushes, or tunes the buffer-dirty-flush daemon. +Only a privileged process (one with the +.B CAP_SYS_ADMIN +capability) may call +.BR bdflush (). +.PP +If +.I func +is negative or 0, and no daemon has been started, then +.BR bdflush () +enters the daemon code and never returns. +.PP +If +.I func +is 1, +some dirty buffers are written to disk. +.PP +If +.I func +is 2 or more and is even (low bit is 0), then +.I address +is the address of a long word, +and the tuning parameter numbered +.RI "(" "func" "\-2)/2" +is returned to the caller in that address. +.PP +If +.I func +is 3 or more and is odd (low bit is 1), then +.I data +is a long word, +and the kernel sets tuning parameter numbered +.RI "(" "func" "\-3)/2" +to that value. +.PP +The set of parameters, their values, and their valid ranges +are defined in the Linux kernel source file +.IR fs/buffer.c . +.SH RETURN VALUE +If +.I func +is negative or 0 and the daemon successfully starts, +.BR bdflush () +never returns. +Otherwise, the return value is 0 on success and \-1 on failure, with +.I errno +set to indicate the error. +.SH ERRORS +.TP +.B EBUSY +An attempt was made to enter the daemon code after +another process has already entered. +.TP +.B EFAULT +.I address +points outside your accessible address space. +.TP +.B EINVAL +An attempt was made to read or write an invalid parameter number, +or to write an invalid value to a parameter. +.TP +.B EPERM +Caller does not have the +.B CAP_SYS_ADMIN +capability. +.SH STANDARDS +Linux. +.SH HISTORY +Since glibc 2.23, glibc no longer supports this obsolete system call. +.SH SEE ALSO +.BR sync (1), +.BR fsync (2), +.BR sync (2) |