235 lines
6.4 KiB
Groff
235 lines
6.4 KiB
Groff
.\" $NetBSD: kprintf.9,v 1.20 2006/07/16 08:25:07 rillig Exp $
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.\"
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.\" Copyright (c) 1998, 2002 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Jeremy Cooper and by Jason R. Thorpe.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the NetBSD
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.\" Foundation, Inc. and its contributors.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd January 15, 2006
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.Dt KPRINTF 9
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.Os
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.Sh NAME
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.Nm printf, snprintf, vprintf, vsnprintf, uprintf, ttyprintf, tprintf
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.Nd kernel formatted output conversion
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.Sh SYNOPSIS
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.In sys/systm.h
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.Ft void
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.Fn "printf" "const char *format" "..."
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.Ft void
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.Fn "printf_nolog" "const char *format" "..."
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.Ft int
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.Fn "snprintf" "char *buf" "size_t size" "const char *format" "..."
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.Ft void
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.Fn "vprintf" "const char *format" "va_list ap"
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.Ft int
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.Fn "vsnprintf" "char *buf" "size_t size" "const char *format" "va_list ap"
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.Ft void
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.Fn "uprintf" "const char *format" "..."
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.Ft void
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.Fn "ttyprintf" "struct tty *tty" "const char *format" "..."
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.In sys/tprintf.h
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.Ft tpr_t
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.Fn "tprintf_open" "struct proc *p"
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.Ft void
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.Fn "tprintf" "tpr_t tpr" "const char *format" "..."
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.Ft void
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.Fn "tprintf_close" "tpr_t tpr"
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.Ft void
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.Fn "aprint_normal" "const char *format" "..."
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.Ft void
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.Fn "aprint_naive" "const char *format" "..."
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.Ft void
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.Fn "aprint_verbose" "const char *format" "..."
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.Ft void
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.Fn "aprint_debug" "const char *format" "..."
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.Ft void
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.Fn "aprint_error" "const char *format" "..."
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.Ft int
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.Fn "aprint_get_error_count" "void"
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.Sh DESCRIPTION
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The
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.Fn printf
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family of functions allows the kernel to send formatted messages to various
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output devices.
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The functions
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.Fn printf
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and
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.Fn vprintf
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send formatted strings to the system console.
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The
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.Fn printf_nolog
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function is identical to
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.Fn printf ,
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except it does not send the data to the system log.
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The functions
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.Fn snprintf
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and
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.Fn vsnprintf
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write output to a string buffer.
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These four functions work similarly to their user space counterparts,
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and are not described in detail here.
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.Pp
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The functions
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.Fn uprintf
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and
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.Fn ttyprintf
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send formatted strings to the current process's controlling tty and a specific
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tty, respectively.
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.Pp
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The
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.Fn tprintf
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function sends formatted strings to a process's controlling tty,
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via a handle of type tpr_t.
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This allows multiple write operations to the tty with a guarantee that the
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tty will be valid across calls.
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A handle is acquired by calling
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.Fn tprintf_open
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with the target process as an argument.
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This handle must be closed with a matching call to
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.Fn tprintf_close .
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.Pp
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The functions
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.Fn aprint_normal ,
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.Fn aprint_naive ,
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.Fn aprint_verbose ,
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.Fn aprint_debug ,
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and
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.Fn aprint_error
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are intended to be used to print autoconfiguration messages, and change
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their behavior based on flags in the
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.Dq boothowto
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variable:
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.Bl -tag -width "aprint_verbose()"
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.It Fn aprint_normal
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Sends to the console unless
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.Dv AB_QUIET
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is set.
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Always sends to the log.
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.It Fn aprint_naive
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Sends to the console only if
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.Dv AB_QUIET
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is set.
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Never sends to the log.
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.It Fn aprint_verbose
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Sends to the console only if
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.Dv AB_VERBOSE
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is set.
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Always sends to the log.
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.It Fn aprint_debug
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Sends to the console and the log only if
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.Dv AB_DEBUG
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is set.
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.It Fn aprint_error
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Like
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.Fn aprint_normal ,
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but also keeps track of the number of times called.
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This allows a subsystem to report the number of errors that occurred
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during a quiet or silent initialization phase.
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The
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.Fn aprint_get_error_count
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function reports the number of errors and resets the counter to 0.
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.El
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.Pp
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If
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.Dv AB_SILENT
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is set, none of the autoconfiguration message printing routines send output
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to the console.
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The
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.Dv AB_VERBOSE
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and
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.Dv AB_DEBUG
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flags override
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.Dv AB_SILENT .
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.Sh RETURN VALUES
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The
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.Fn snprintf
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and
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.Fn vsnprintf
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functions return the number of characters placed in the buffer
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.Fa buf .
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This is different to the user-space functions of the same name.
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.Pp
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The
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.Fn tprintf_open
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function returns
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.Dv NULL
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if no terminal handle could be acquired.
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.Sh SEE ALSO
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.Xr printf 1 ,
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.Xr printf 3 ,
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.Xr bitmask_snprintf 9
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.Sh CODE REFERENCES
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.Pa sys/kern/subr_prf.c
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.Sh HISTORY
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The
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.Fn sprintf
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and
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.Fn vsprintf
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unsized string formatting functions are supported for compatibility only,
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and are not documented here.
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New code should use the size-limited
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.Fn snprintf
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and
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.Fn vsnprintf
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functions instead.
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.Pp
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In
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.Nx 1.5
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and earlier,
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.Fn printf
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supported more format strings than the user space
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.Fn printf .
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These nonstandard format strings are no longer supported.
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For the functionality provided by the former
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.Li %b
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format string, see
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.Xr bitmask_snprintf 9 .
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.Pp
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The
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.Fn aprint_normal ,
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.Fn aprint_naive ,
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.Fn aprint_verbose ,
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and
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.Fn aprint_debug
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functions first appeared in
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.Bsx .
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.Sh BUGS
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The
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.Fn uprintf
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and
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.Fn ttyprintf
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functions should be used sparingly, if at all.
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Where multiple lines of output are required to reach a process's
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controlling terminal,
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.Fn tprintf
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is preferred.
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