# Notes on the locale implementation.

prepared by Benjamin Kosnik (bkoz@redhat.com) on September 15, 2000

## 1. Abstract

## 2. What the standard says

## 3. Problems with "C" locales : global locales, termination.

For the required specialization codecvt<wchar_t, char, mbstate_t> , conversions are made between the internal character set (always UCS4 on GNU/Linux) and whatever the currently selected locale for the LC_CTYPE category implements.

## 4. Design

The two required specializations are implemented as follows:

## 5. Examples

      typedef ctype<char> cctype;

More information can be found in the following testcases:

- testsuite/22_locale/ctype_char_members.cc
- testsuite/22_locale/ctype_wchar_t_members.cc

## 6. Unresolved Issues

- locale -a displays available locales on linux
- locale initialization: at what point does _S_classic, _S_global get initialized? Can named locales assume this initialization has already taken place?

## 7. Acknowledgments

## 8. Bibliography / Referenced Documents

Drepper, Ulrich, GNU libc (glibc) 2.2 manual. In particular, Chapters "6. Character Set Handling" and "7 Locales and Internationalization"

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