b6cbf7203b
This patch imports the unmodified current version of NetBSD libc. The NetBSD includes are in /nbsd_include, while the libc code itself is split between lib/nbsd_libc and common/lib/libc.
618 lines
16 KiB
Groff
618 lines
16 KiB
Groff
.\" $NetBSD: wprintf.3,v 1.8 2010/12/16 17:42:27 wiz Exp $
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.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" Chris Torek and the American National Standards Committee X3,
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.\" on Information Processing Systems.
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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 University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)printf.3 8.1 (Berkeley) 6/4/93
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.\" FreeBSD: src/lib/libc/stdio/printf.3,v 1.47 2002/09/06 11:23:55 tjr Exp
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.\" $FreeBSD: src/lib/libc/stdio/wprintf.3,v 1.5 2003/07/05 07:55:34 tjr Exp $
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.\"
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.Dd April 30, 2010
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.Dt WPRINTF 3
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.Os
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.Sh NAME
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.Nm wprintf , fwprintf , swprintf ,
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.Nm vwprintf , vfwprintf , vswprintf
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.Nd formatted wide character output conversion
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdio.h
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.In wchar.h
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.Ft int
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.Fn fwprintf "FILE * restrict stream" "const wchar_t * restrict format" ...
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.Ft int
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.Fn swprintf "wchar_t * restrict ws" "size_t n" "const wchar_t * restrict format" ...
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.Ft int
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.Fn wprintf "const wchar_t * restrict format" ...
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.In stdarg.h
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.Ft int
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.Fn vfwprintf "FILE * restrict stream" "const wchar_t * restrict" "va_list ap"
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.Ft int
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.Fn vswprintf "wchar_t * restrict ws" "size_t n" "const wchar_t *restrict format" "va_list ap"
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.Ft int
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.Fn vwprintf "const wchar_t * restrict format" "va_list ap"
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.Sh DESCRIPTION
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The
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.Fn wprintf
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family of functions produces output according to a
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.Fa format
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as described below.
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The
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.Fn wprintf
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and
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.Fn vwprintf
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functions
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write output to
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.Dv stdout ,
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the standard output stream;
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.Fn fwprintf
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and
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.Fn vfwprintf
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write output to the given output
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.Fa stream ;
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.Fn swprintf
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and
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.Fn vswprintf
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write to the wide-character string
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.Fa ws .
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.Pp
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These functions write the output under the control of a
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.Fa format
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string that specifies how subsequent arguments
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(or arguments accessed via the variable-length argument facilities of
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.Xr stdarg 3 )
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are converted for output.
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.Pp
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The
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.Fn swprintf
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and
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.Fn vswprintf
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functions will fail if
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.Fa n
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or more wide characters were requested to be written,
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.Pp
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The format string is composed of zero or more directives:
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ordinary
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characters (not
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.Cm % ) ,
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which are copied unchanged to the output stream;
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and conversion specifications, each of which results
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in fetching zero or more subsequent arguments.
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Each conversion specification is introduced by
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the
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.Cm %
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character.
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The arguments must correspond properly (after type promotion)
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with the conversion specifier.
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After the
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.Cm % ,
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the following appear in sequence:
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.Bl -bullet
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.It
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An optional field, consisting of a decimal digit string followed by a
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.Cm $ ,
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specifying the next argument to access.
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If this field is not provided, the argument following the last
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argument accessed will be used.
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Arguments are numbered starting at
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.Cm 1 .
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If unaccessed arguments in the format string are interspersed with ones that
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are accessed the results will be indeterminate.
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.It
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Zero or more of the following flags:
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.Bl -tag -width ".So \ Sc (space)"
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.It Sq Cm #
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The value should be converted to an
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.Dq alternate form .
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For
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.Cm c , d , i , n , p , s ,
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and
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.Cm u
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conversions, this option has no effect.
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For
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.Cm o
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conversions, the precision of the number is increased to force the first
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character of the output string to a zero (except if a zero value is printed
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with an explicit precision of zero).
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For
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.Cm x
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and
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.Cm X
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conversions, a non-zero result has the string
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.Ql 0x
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(or
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.Ql 0X
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for
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.Cm X
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conversions) prepended to it.
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For
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.Cm a , A , e , E , f , F , g ,
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and
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.Cm G
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conversions, the result will always contain a decimal point, even if no
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digits follow it (normally, a decimal point appears in the results of
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those conversions only if a digit follows).
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For
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.Cm g
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and
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.Cm G
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conversions, trailing zeros are not removed from the result as they
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would otherwise be.
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.It So Cm 0 Sc (zero)
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Zero padding.
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For all conversions except
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.Cm n ,
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the converted value is padded on the left with zeros rather than blanks.
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If a precision is given with a numeric conversion
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.Cm ( d , i , o , u , i , x ,
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and
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.Cm X ) ,
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the
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.Cm 0
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flag is ignored.
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.It Sq Cm \-
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A negative field width flag;
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the converted value is to be left adjusted on the field boundary.
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Except for
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.Cm n
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conversions, the converted value is padded on the right with blanks,
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rather than on the left with blanks or zeros.
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A
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.Cm \-
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overrides a
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.Cm 0
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if both are given.
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.It So "\ " Sc (space)
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A blank should be left before a positive number
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produced by a signed conversion
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.Cm ( a , A , d , e , E , f , F , g , G ,
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or
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.Cm i ) .
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.It Sq Cm +
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A sign must always be placed before a
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number produced by a signed conversion.
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A
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.Cm +
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overrides a space if both are used.
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.It Sq Cm '
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Decimal conversions
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.Cm ( d , u ,
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or
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.Cm i )
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or the integral portion of a floating point conversion
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.Cm ( f
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or
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.Cm F )
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should be grouped and separated by thousands using
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the non-monetary separator returned by
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.Xr localeconv 3 .
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.El
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.It
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An optional decimal digit string specifying a minimum field width.
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If the converted value has fewer characters than the field width, it will
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be padded with spaces on the left (or right, if the left-adjustment
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flag has been given) to fill out
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the field width.
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.It
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An optional precision, in the form of a period
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.Cm \&.
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followed by an
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optional digit string.
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If the digit string is omitted, the precision is taken as zero.
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This gives the minimum number of digits to appear for
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.Cm d , i , o , u , x ,
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and
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.Cm X
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conversions, the number of digits to appear after the decimal-point for
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.Cm a , A , e , E , f ,
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and
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.Cm F
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conversions, the maximum number of significant digits for
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.Cm g
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and
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.Cm G
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conversions, or the maximum number of characters to be printed from a
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string for
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.Cm s
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conversions.
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.It
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An optional length modifier, that specifies the size of the argument.
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The following length modifiers are valid for the
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.Cm d , i , n , o , u , x ,
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or
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.Cm X
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conversion:
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.Bl -column ".Cm q Em (deprecated)" ".Vt signed char" ".Vt unsigned long long" ".Vt long long *"
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.It Sy Modifier Ta Cm d , i Ta Cm o , u , x , X Ta Cm n
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.It Cm hh Ta Vt "signed char" Ta Vt "unsigned char" Ta Vt "signed char *"
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.It Cm h Ta Vt short Ta Vt "unsigned short" Ta Vt "short *"
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.It Cm l No (ell) Ta Vt long Ta Vt "unsigned long" Ta Vt "long *"
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.It Cm ll No (ell ell) Ta Vt "long long" Ta Vt "unsigned long long" Ta Vt "long long *"
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.It Cm j Ta Vt intmax_t Ta Vt uintmax_t Ta Vt "intmax_t *"
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.It Cm t Ta Vt ptrdiff_t Ta (see note) Ta Vt "ptrdiff_t *"
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.It Cm z Ta (see note) Ta Vt size_t Ta (see note)
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.It Cm q Em (deprecated) Ta Vt quad_t Ta Vt u_quad_t Ta Vt "quad_t *"
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.El
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.Pp
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|
Note:
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the
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.Cm t
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modifier, when applied to a
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.Cm o , u , x ,
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or
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.Cm X
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|
conversion, indicates that the argument is of an unsigned type
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equivalent in size to a
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.Vt ptrdiff_t .
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The
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.Cm z
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modifier, when applied to a
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.Cm d
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or
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.Cm i
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conversion, indicates that the argument is of a signed type equivalent in
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size to a
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.Vt size_t .
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Similarly, when applied to an
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.Cm n
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conversion, it indicates that the argument is a pointer to a signed type
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equivalent in size to a
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.Vt size_t .
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.Pp
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The following length modifier is valid for the
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.Cm a , A , e , E , f , F , g ,
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or
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.Cm G
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conversion:
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.Bl -column ".Sy Modifier" ".Cm a , A , e , E , f , F , g , G"
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.It Sy Modifier Ta Cm a , A , e , E , f , F , g , G
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.It Cm L Ta Vt "long double"
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.El
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.Pp
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The following length modifier is valid for the
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.Cm c
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or
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.Cm s
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conversion:
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.Bl -column ".Sy Modifier" ".Vt wint_t" ".Vt wchar_t *"
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.It Sy Modifier Ta Cm c Ta Cm s
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.It Cm l No (ell) Ta Vt wint_t Ta Vt "wchar_t *"
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.El
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.It
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A character that specifies the type of conversion to be applied.
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.El
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.Pp
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A field width or precision, or both, may be indicated by
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an asterisk
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.Ql *
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or an asterisk followed by one or more decimal digits and a
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.Ql $
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instead of a
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digit string.
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In this case, an
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.Vt int
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argument supplies the field width or precision.
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A negative field width is treated as a left adjustment flag followed by a
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positive field width; a negative precision is treated as though it were
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missing.
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If a single format directive mixes positional
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.Pq Li nn$
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and non-positional arguments, the results are undefined.
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.Pp
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The conversion specifiers and their meanings are:
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.Bl -tag -width ".Cm diouxX"
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.It Cm diouxX
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The
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.Vt int
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(or appropriate variant) argument is converted to signed decimal
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.Cm ( d
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and
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.Cm i ) ,
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unsigned octal
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.Pq Cm o ,
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unsigned decimal
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.Pq Cm u ,
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or unsigned hexadecimal
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.Cm ( x
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and
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.Cm X )
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notation.
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The letters
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.Dq Li abcdef
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are used for
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.Cm x
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conversions; the letters
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.Dq Li ABCDEF
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are used for
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.Cm X
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conversions.
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The precision, if any, gives the minimum number of digits that must
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appear; if the converted value requires fewer digits, it is padded on
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the left with zeros.
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.It Cm DOU
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The
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.Vt "long int"
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argument is converted to signed decimal, unsigned octal, or unsigned
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decimal, as if the format had been
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.Cm ld , lo ,
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or
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.Cm lu
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respectively.
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These conversion characters are deprecated, and will eventually disappear.
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.It Cm eE
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The
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.Vt double
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argument is rounded and converted in the style
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.Sm off
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.Oo \- Oc Ar d Li \&. Ar ddd Li e \*[Pm] Ar dd
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.Sm on
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where there is one digit before the
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decimal-point character
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and the number of digits after it is equal to the precision;
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if the precision is missing,
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it is taken as 6; if the precision is
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zero, no decimal-point character appears.
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An
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.Cm E
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conversion uses the letter
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.Ql E
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(rather than
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.Ql e )
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to introduce the exponent.
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The exponent always contains at least two digits; if the value is zero,
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the exponent is 00.
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.Pp
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For
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.Cm a , A , e , E , f , F , g ,
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and
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.Cm G
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conversions, positive and negative infinity are represented as
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.Li inf
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and
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.Li -inf
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respectively when using the lowercase conversion character, and
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.Li INF
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and
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.Li -INF
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respectively when using the uppercase conversion character.
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Similarly, NaN is represented as
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.Li nan
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when using the lowercase conversion, and
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.Li NAN
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when using the uppercase conversion.
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.It Cm fF
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The
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.Vt double
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argument is rounded and converted to decimal notation in the style
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.Sm off
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.Oo \- Oc Ar ddd Li \&. Ar ddd ,
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.Sm on
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where the number of digits after the decimal-point character
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is equal to the precision specification.
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If the precision is missing, it is taken as 6; if the precision is
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explicitly zero, no decimal-point character appears.
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If a decimal point appears, at least one digit appears before it.
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.It Cm gG
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The
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.Vt double
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argument is converted in style
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.Cm f
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or
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.Cm e
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(or
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.Cm F
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or
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.Cm E
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|
for
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.Cm G
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|
conversions).
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The precision specifies the number of significant digits.
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If the precision is missing, 6 digits are given; if the precision is zero,
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it is treated as 1.
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Style
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.Cm e
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is used if the exponent from its conversion is less than \-4 or greater than
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or equal to the precision.
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Trailing zeros are removed from the fractional part of the result; a
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decimal point appears only if it is followed by at least one digit.
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.It Cm aA
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The
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.Vt double
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|
argument is converted to hexadecimal notation in the style
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|
.Sm off
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|
.Oo \- Oc Li 0x Ar h Li \&. Ar hhhp Oo \*[Pm] Oc Ar d ,
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.Sm on
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|
where the number of digits after the hexadecimal-point character
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is equal to the precision specification.
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If the precision is missing, it is taken as enough to exactly
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represent the floating-point number; if the precision is
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explicitly zero, no hexadecimal-point character appears.
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This is an exact conversion of the mantissa+exponent internal
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|
floating point representation; the
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|
.Sm off
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|
.Oo \- Oc Li 0x Ar h Li \&. Ar hhh
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.Sm on
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portion represents exactly the mantissa; only denormalized
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mantissas have a zero value to the left of the hexadecimal
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|
point.
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The
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.Cm p
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|
is a literal character
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|
.Ql p ;
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the exponent is preceded by a positive or negative sign
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and is represented in decimal, using only enough characters
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to represent the exponent.
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The
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.Cm A
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|
conversion uses the prefix
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.Dq Li 0X
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(rather than
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|
.Dq Li 0x ) ,
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the letters
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.Dq Li ABCDEF
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|
(rather than
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|
.Dq Li abcdef )
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|
to represent the hex digits, and the letter
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.Ql P
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|
(rather than
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.Ql p )
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|
to separate the mantissa and exponent.
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|
.It Cm C
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|
Treated as
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.Cm c
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with the
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.Cm l
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(ell) modifier.
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.It Cm c
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The
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.Vt int
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argument is converted to an
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.Vt "unsigned char" ,
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then to a
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.Vt wchar_t
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as if by
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.Xr btowc 3 ,
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and the resulting character is written.
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.Pp
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If the
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.Cm l
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(ell) modifier is used, the
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.Vt wint_t
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argument is converted to a
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.Vt wchar_t
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and written.
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.It Cm S
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Treated as
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.Cm s
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with the
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.Cm l
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(ell) modifier.
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.It Cm s
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The
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.Vt "char *"
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|
argument is expected to be a pointer to an array of character type (pointer
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to a string) containing a multibyte sequence.
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Characters from the array are converted to wide characters and written up to
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(but not including)
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a terminating
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|
.Dv NUL
|
|
character;
|
|
if a precision is specified, no more than the number specified are
|
|
written.
|
|
If a precision is given, no null character
|
|
need be present; if the precision is not specified, or is greater than
|
|
the size of the array, the array must contain a terminating
|
|
.Dv NUL
|
|
character.
|
|
.Pp
|
|
If the
|
|
.Cm l
|
|
(ell) modifier is used, the
|
|
.Vt "wchar_t *"
|
|
argument is expected to be a pointer to an array of wide characters
|
|
(pointer to a wide string).
|
|
Each wide character in the string
|
|
is written.
|
|
Wide characters from the array are written up to (but not including)
|
|
a terminating wide
|
|
.Dv NUL
|
|
character;
|
|
if a precision is specified, no more than the number specified are
|
|
written (including shift sequences).
|
|
If a precision is given, no null character
|
|
need be present; if the precision is not specified, or is greater than
|
|
the number of characters in
|
|
the string, the array must contain a terminating wide
|
|
.Dv NUL
|
|
character.
|
|
.It Cm p
|
|
The
|
|
.Vt "void *"
|
|
pointer argument is printed in hexadecimal (as if by
|
|
.Ql %#x
|
|
or
|
|
.Ql %#lx ) .
|
|
.It Cm n
|
|
The number of characters written so far is stored into the
|
|
integer indicated by the
|
|
.Vt "int *"
|
|
(or variant) pointer argument.
|
|
No argument is converted.
|
|
.It Cm %
|
|
A
|
|
.Ql %
|
|
is written.
|
|
No argument is converted.
|
|
The complete conversion specification
|
|
is
|
|
.Ql %% .
|
|
.El
|
|
.Pp
|
|
The decimal point
|
|
character is defined in the program's locale (category
|
|
.Dv LC_NUMERIC ) .
|
|
.Pp
|
|
In no case does a non-existent or small field width cause truncation of
|
|
a numeric field; if the result of a conversion is wider than the field
|
|
width, the
|
|
field is expanded to contain the conversion result.
|
|
.Sh RETURN VALUES
|
|
These functions return the number of characters printed
|
|
(not including the trailing
|
|
.Ql \e0
|
|
used to end output to strings).
|
|
.Sh SEE ALSO
|
|
.Xr btowc 3 ,
|
|
.Xr fputws 3 ,
|
|
.Xr printf 3 ,
|
|
.Xr putwc 3 ,
|
|
.Xr setlocale 3 ,
|
|
.Xr wcsrtombs 3 ,
|
|
.Xr wscanf 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn wprintf ,
|
|
.Fn fwprintf ,
|
|
.Fn swprintf ,
|
|
.Fn vwprintf ,
|
|
.Fn vfwprintf
|
|
and
|
|
.Fn vswprintf
|
|
functions
|
|
conform to
|
|
.St -isoC-99 .
|
|
.Sh SECURITY CONSIDERATIONS
|
|
Subject to the caveats noted in the
|
|
.Xr printf 3 .
|