Describes the basic locale object, including nested classes id, facet, and the reference-counted implementation object, class _Impl.
class facet 22.1.1.1.2 Class locale::facet
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.
Literally, a facet is strictly defined:
static locale::id id;
class gnu_codecvt: public std::ctype<user-defined-type>
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.
class id 22.1.1.1.3 - Class locale::id
Provides an index for looking up specific facets.
Some help on determining the underlying support for locales on a system. Note, this is specific to linux (and glibc-2.3.x)
`locale -a` displays available locales.
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
`locale` displays environmental variables
that impact how locale("") will be deduced.
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=
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:
std::locale::global(std::locale(""));
affects the C functions as if the following call was made:
std::setlocale(LC_ALL, "");
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.
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.)
Because POSIX falls down so completely, portibility is an issue.
class _Impl The internal representation of the std::locale object.Drepper, Ulrich, Numerous, late-night email correspondence
ISO/IEC 14882:1998 Programming languages - C++
ISO/IEC 9899:1999 Programming languages - C
Langer, Angelika and Klaus Kreft, Standard C++ IOStreams and Locales, Advanced Programmer's Guide and Reference, Addison Wesley Longman, Inc. 2000
Stroustrup, Bjarne, Appendix D, The C++ Programming Language, Special Edition, Addison Wesley, Inc. 2000
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