mirror of https://github.com/mkerrisk/man-pages
129 lines
2.8 KiB
Groff
129 lines
2.8 KiB
Groff
.\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
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.\" and Copyright (C) 2014 Michael Kerrisk <mtk.manpages@gmail.com>
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.\"
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.\" %%%LICENSE_START(GPLv2+_DOC_ONEPARA)
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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.\" %%%LICENSE_END
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.\"
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.\" References consulted:
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.\" GNU glibc-2 source code and manual
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.\" Dinkumware C library reference http://www.dinkumware.com/
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.\" OpenGroup's Single UNIX specification http://www.UNIX-systems.org/online.html
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.\" ISO/IEC 9899:1999
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.\"
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.TH TOWLOWER 3 2017-09-15 "GNU" "Linux Programmer's Manual"
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.SH NAME
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towlower, towlower_l \- convert a wide character to lowercase
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.SH SYNOPSIS
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.nf
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.B #include <wctype.h>
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.PP
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.BI "wint_t towlower(wint_t " wc );
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.PP
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.BI "wint_t towlower_l(wint_t " wc ", locale_t " locale );
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.fi
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.PP
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.RS -4
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Feature Test Macro Requirements for glibc (see
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.BR feature_test_macros (7)):
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.RE
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.PP
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.BR towlower_l ():
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.PD 0
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.RS 4
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.TP
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Since glibc 2.10:
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_XOPEN_SOURCE\ >=\ 700
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.TP
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Before glibc 2.10:
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_GNU_SOURCE
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.RE
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.PD
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.SH DESCRIPTION
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The
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.BR towlower ()
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function is the wide-character equivalent of the
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.BR tolower (3)
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function.
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If
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.I wc
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is an uppercase wide character,
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and there exists a lowercase equivalent in the current locale,
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it returns the lowercase equivalent of
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.IR wc .
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In all other cases,
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.I wc
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is returned unchanged.
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.PP
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The
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.BR towlower_l ()
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function performs the same task,
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but performs the conversion based on the character type information in
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the locale specified by
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.IR locale .
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The behavior of
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.BR towlower_l ()
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is undefined if
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.I locale
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is the special locale object
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.B LC_GLOBAL_LOCALE
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(see
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.BR duplocale (3))
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or is not a valid locale object handle.
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.PP
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The argument
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.I wc
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must be representable as a
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.I wchar_t
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and be a valid character in the locale or be the value
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.BR WEOF .
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.SH RETURN VALUE
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If
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.I wc
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was convertible to lowercase,
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.BR towlower ()
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returns its lowercase equivalent;
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otherwise it returns
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.IR wc .
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.SH VERSIONS
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The
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.BR towlower_l ()
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function first appeared in glibc 2.3.
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.SH ATTRIBUTES
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For an explanation of the terms used in this section, see
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.BR attributes (7).
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.TS
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allbox;
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lb lb lb
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l l l.
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Interface Attribute Value
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T{
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.BR towlower ()
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T} Thread safety MT-Safe locale
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T{
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.BR towlower_l ()
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T} Thread safety MT-Safe
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.TE
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.SH CONFORMING TO
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.BR towlower ():
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C99, POSIX.1-2001 (XSI);
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present as an XSI extension in POSIX.1-2008, but marked obsolete.
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.PP
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.BR towlower_l ():
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POSIX.1-2008.
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.SH NOTES
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The behavior of these functions depends on the
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.B LC_CTYPE
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category of the locale.
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.PP
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These functions are not very appropriate for dealing with Unicode characters,
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because Unicode knows about three cases: upper, lower and title case.
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.SH SEE ALSO
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.BR iswlower (3),
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.BR towctrans (3),
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.BR towupper (3),
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.BR locale (7)
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