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diff --git a/libstdc++-v3/doc/html/22_locale/locale.html b/libstdc++-v3/doc/html/22_locale/locale.html new file mode 100644 index 00000000000..57ef5b4e981 --- /dev/null +++ b/libstdc++-v3/doc/html/22_locale/locale.html @@ -0,0 +1,543 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE html + PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> + +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> +<head> + <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> + <meta name="AUTHOR" content="bkoz@redhat.com (Benjamin Kosnik)" /> + <meta name="KEYWORDS" content="HOWTO, libstdc++, locale name LC_ALL" /> + <meta name="DESCRIPTION" content="Notes on the locale implementation." /> + <title>Notes on the locale implementation.</title> +<link rel="StyleSheet" href="../lib3styles.css" type="text/css" /> +<link rel="Start" href="../documentation.html" type="text/html" + title="GNU C++ Standard Library" /> +<link rel="Bookmark" href="howto.html" type="text/html" title="Localization" /> +<link rel="Copyright" href="../17_intro/license.html" type="text/html" /> +<link rel="Help" href="../faq/index.html" type="text/html" title="F.A.Q." /> +</head> +<body> + <h1> + Notes on the locale implementation. + </h1> +<em> +prepared by Benjamin Kosnik (bkoz@redhat.com) on October 14, 2002 +</em> + +<h2> +1. Abstract +</h2> +<p> +Describes the basic locale object, including nested +classes id, facet, and the reference-counted implementation object, +class _Impl. +</p> + +<h2> +2. What the standard says +</h2> +Class locale is non-templatized and has two distinct types nested +inside of it: + +<blockquote> +<em> +class facet +22.1.1.1.2 Class locale::facet +</em> +</blockquote> + +<p> +Facets actually implement locale functionality. For instance, a facet +called numpunct is the data objects that can be used to query for the +thousands separator is in the German locale. +</p> + +Literally, a facet is strictly defined: +<ul> + <li>containing the following public data member: + <p> + <code>static locale::id id;</code> + </p> + </li> + + <li>derived from another facet: + <p> + <code> class gnu_codecvt: public std::ctype<user-defined-type></code> + </p> + </li> +</ul> + +<p> +Of interest in this class are the memory management options explicitly +specified as an argument to facet's constructor. Each constructor of a +facet class takes a std::size_t __refs argument: if __refs == 0, the +facet is deleted when the locale containing it is destroyed. If __refs +== 1, the facet is not destroyed, even when it is no longer +referenced. +</p> + +<blockquote> +<em> +class id +22.1.1.1.3 - Class locale::id +</em> +</blockquote> + +<p> +Provides an index for looking up specific facets. +</p> + + +<h2> +3. Interacting with "C" locales. +</h2> + +<p> +Some help on determining the underlying support for locales on a system. +Note, this is specific to linux (and glibc-2.3.x) +</p> + +<ul> + <li> <code>`locale -a`</code> displays available locales. +<blockquote> +<pre> +af_ZA +ar_AE +ar_AE.utf8 +ar_BH +ar_BH.utf8 +ar_DZ +ar_DZ.utf8 +ar_EG +ar_EG.utf8 +ar_IN +ar_IQ +ar_IQ.utf8 +ar_JO +ar_JO.utf8 +ar_KW +ar_KW.utf8 +ar_LB +ar_LB.utf8 +ar_LY +ar_LY.utf8 +ar_MA +ar_MA.utf8 +ar_OM +ar_OM.utf8 +ar_QA +ar_QA.utf8 +ar_SA +ar_SA.utf8 +ar_SD +ar_SD.utf8 +ar_SY +ar_SY.utf8 +ar_TN +ar_TN.utf8 +ar_YE +ar_YE.utf8 +be_BY +be_BY.utf8 +bg_BG +bg_BG.utf8 +br_FR +bs_BA +C +ca_ES +ca_ES@euro +ca_ES.utf8 +ca_ES.utf8@euro +cs_CZ +cs_CZ.utf8 +cy_GB +da_DK +da_DK.iso885915 +da_DK.utf8 +de_AT +de_AT@euro +de_AT.utf8 +de_AT.utf8@euro +de_BE +de_BE@euro +de_BE.utf8 +de_BE.utf8@euro +de_CH +de_CH.utf8 +de_DE +de_DE@euro +de_DE.utf8 +de_DE.utf8@euro +de_LU +de_LU@euro +de_LU.utf8 +de_LU.utf8@euro +el_GR +el_GR.utf8 +en_AU +en_AU.utf8 +en_BW +en_BW.utf8 +en_CA +en_CA.utf8 +en_DK +en_DK.utf8 +en_GB +en_GB.iso885915 +en_GB.utf8 +en_HK +en_HK.utf8 +en_IE +en_IE@euro +en_IE.utf8 +en_IE.utf8@euro +en_IN +en_NZ +en_NZ.utf8 +en_PH +en_PH.utf8 +en_SG +en_SG.utf8 +en_US +en_US.iso885915 +en_US.utf8 +en_ZA +en_ZA.utf8 +en_ZW +en_ZW.utf8 +es_AR +es_AR.utf8 +es_BO +es_BO.utf8 +es_CL +es_CL.utf8 +es_CO +es_CO.utf8 +es_CR +es_CR.utf8 +es_DO +es_DO.utf8 +es_EC +es_EC.utf8 +es_ES +es_ES@euro +es_ES.utf8 +es_ES.utf8@euro +es_GT +es_GT.utf8 +es_HN +es_HN.utf8 +es_MX +es_MX.utf8 +es_NI +es_NI.utf8 +es_PA +es_PA.utf8 +es_PE +es_PE.utf8 +es_PR +es_PR.utf8 +es_PY +es_PY.utf8 +es_SV +es_SV.utf8 +es_US +es_US.utf8 +es_UY +es_UY.utf8 +es_VE +es_VE.utf8 +et_EE +et_EE.utf8 +eu_ES +eu_ES@euro +eu_ES.utf8 +eu_ES.utf8@euro +fa_IR +fi_FI +fi_FI@euro +fi_FI.utf8 +fi_FI.utf8@euro +fo_FO +fo_FO.utf8 +fr_BE +fr_BE@euro +fr_BE.utf8 +fr_BE.utf8@euro +fr_CA +fr_CA.utf8 +fr_CH +fr_CH.utf8 +fr_FR +fr_FR@euro +fr_FR.utf8 +fr_FR.utf8@euro +fr_LU +fr_LU@euro +fr_LU.utf8 +fr_LU.utf8@euro +ga_IE +ga_IE@euro +ga_IE.utf8 +ga_IE.utf8@euro +gl_ES +gl_ES@euro +gl_ES.utf8 +gl_ES.utf8@euro +gv_GB +gv_GB.utf8 +he_IL +he_IL.utf8 +hi_IN +hr_HR +hr_HR.utf8 +hu_HU +hu_HU.utf8 +id_ID +id_ID.utf8 +is_IS +is_IS.utf8 +it_CH +it_CH.utf8 +it_IT +it_IT@euro +it_IT.utf8 +it_IT.utf8@euro +iw_IL +iw_IL.utf8 +ja_JP.eucjp +ja_JP.utf8 +ka_GE +kl_GL +kl_GL.utf8 +ko_KR.euckr +ko_KR.utf8 +kw_GB +kw_GB.utf8 +lt_LT +lt_LT.utf8 +lv_LV +lv_LV.utf8 +mi_NZ +mk_MK +mk_MK.utf8 +mr_IN +ms_MY +ms_MY.utf8 +mt_MT +mt_MT.utf8 +nl_BE +nl_BE@euro +nl_BE.utf8 +nl_BE.utf8@euro +nl_NL +nl_NL@euro +nl_NL.utf8 +nl_NL.utf8@euro +nn_NO +nn_NO.utf8 +no_NO +no_NO.utf8 +oc_FR +pl_PL +pl_PL.utf8 +POSIX +pt_BR +pt_BR.utf8 +pt_PT +pt_PT@euro +pt_PT.utf8 +pt_PT.utf8@euro +ro_RO +ro_RO.utf8 +ru_RU +ru_RU.koi8r +ru_RU.utf8 +ru_UA +ru_UA.utf8 +se_NO +sk_SK +sk_SK.utf8 +sl_SI +sl_SI.utf8 +sq_AL +sq_AL.utf8 +sr_YU +sr_YU@cyrillic +sr_YU.utf8 +sr_YU.utf8@cyrillic +sv_FI +sv_FI@euro +sv_FI.utf8 +sv_FI.utf8@euro +sv_SE +sv_SE.iso885915 +sv_SE.utf8 +ta_IN +te_IN +tg_TJ +th_TH +th_TH.utf8 +tl_PH +tr_TR +tr_TR.utf8 +uk_UA +uk_UA.utf8 +ur_PK +uz_UZ +vi_VN +vi_VN.tcvn +wa_BE +wa_BE@euro +yi_US +zh_CN +zh_CN.gb18030 +zh_CN.gbk +zh_CN.utf8 +zh_HK +zh_HK.utf8 +zh_TW +zh_TW.euctw +zh_TW.utf8 +</pre> +</blockquote> +</li> + + <li> <code>`locale`</code> displays environmental variables + that impact how locale("") will be deduced. + +<blockquote> +<pre> +LANG=en_US +LC_CTYPE="en_US" +LC_NUMERIC="en_US" +LC_TIME="en_US" +LC_COLLATE="en_US" +LC_MONETARY="en_US" +LC_MESSAGES="en_US" +LC_PAPER="en_US" +LC_NAME="en_US" +LC_ADDRESS="en_US" +LC_TELEPHONE="en_US" +LC_MEASUREMENT="en_US" +LC_IDENTIFICATION="en_US" +LC_ALL= +</pre> +</blockquote> +</li> +</ul> + +<p> +From Josuttis, p. 697-698, which says, that "there is only *one* +relation (of the C++ locale mechanism) to the C locale mechanism: the +global C locale is modified if a named C++ locale object is set as the +global locale" (emphasis Paolo), that is: +</p> + <code>std::locale::global(std::locale(""));</code> + +<p>affects the C functions as if the following call was made:</p> + + <code>std::setlocale(LC_ALL, "");</code> + +<p> +On the other hand, there is *no* viceversa, that is, calling setlocale +has *no* whatsoever on the C++ locale mechanism, in particular on the +working of locale(""), which constructs the locale object from the +environment of the running program, that is, in practice, the set of +LC_ALL, LANG, etc. variable of the shell. +</p> + + +<h2> +4. Design +</h2> + + +<p> +The major design challenge is fitting an object-orientated and +non-global locale design ontop of POSIX and other relevant stanards, +which include the Single Unix (nee X/Open.) +</p> + +<p> +Because POSIX falls down so completely, portibility is an issue. +</p> + +class _Impl +The internal representation of the std::locale object. + + +<h2> +5. Examples +</h2> + +More information can be found in the following testcases: +<ul> +<li> testsuite/22_locale/all </li> +</ul> + +<h2> +6. Unresolved Issues +</h2> + +<ul> + <li> locale initialization: at what point does _S_classic, + _S_global get initialized? Can named locales assume this + initialization has already taken place? </li> + + <li> document how named locales error check when filling data + members. Ie, a fr_FR locale that doesn't have + numpunct::truename(): does it use "true"? Or is it a blank + string? What's the convention? </li> + + <li> explain how locale aliasing happens. When does "de_DE" + use "de" information? What is the rule for locales composed of + just an ISO language code (say, "de") and locales with both an + ISO language code and ISO country code (say, "de_DE"). </li> + + <li> what should non-required facet instantiations do? If the + generic implemenation is provided, then how to end-users + provide specializations? </li> +</ul> + +<h2> +7. Acknowledgments +</h2> + +<h2> +8. Bibliography / Referenced Documents +</h2> + +Drepper, Ulrich, GNU libc (glibc) 2.2 manual. In particular, Chapters "6. Character Set Handling" and "7 Locales and Internationalization" + +<p> +Drepper, Ulrich, Numerous, late-night email correspondence +</p> + +<p> +ISO/IEC 14882:1998 Programming languages - C++ +</p> + +<p> +ISO/IEC 9899:1999 Programming languages - C +</p> + +<p> +Langer, Angelika and Klaus Kreft, Standard C++ IOStreams and Locales, Advanced Programmer's Guide and Reference, Addison Wesley Longman, Inc. 2000 +</p> + +<p> +Stroustrup, Bjarne, Appendix D, The C++ Programming Language, Special Edition, Addison Wesley, Inc. 2000 +</p> + +<p> +System Interface Definitions, Issue 6 (IEEE Std. 1003.1-200x) +The Open Group/The Institute of Electrical and Electronics Engineers, Inc. +http://www.opennc.org/austin/docreg.html +</p> + +</body> +</html> + + |
