2    Terminology and General Requirements

2.4    Character Set

2.4.1    Character Set Description File

[41:1181] It is implementation defined whether or not users or applications can provide additional character set description files.

The operating system allows users or applications to provide additional character set description files.

[44:1285] The manner in which these constants are represented in the character stored in the system is implementation defined.

The operating system stores multibyte constants as hexadecimal values, but is capable of handling decimal or octal values as well.

2.5    Locale

[45:1327] If the locale value does not begin with a slash, the mechanism used to locate the locale is implementation defined.

If the locale value does not begin with a slash, the operating system checks the LOCPATH environment variable that defines the search path for locales. The default is: 

LOCPATH=/usr/lib/nls/loc:

2.5.2    Locale Definition

2.5.2.5    LC_TIME

[66:2270] It is implementation defined whether the following optional keywords shall be recognized.

The operating system recognizes the optional keywords era, era_year, era_d_fmt, and alt_digits.

2.5.3    Locale Definition Grammar

[67:2314] Any grammars for additional categories and keywords are implementation defined.

The operating system provides no additional categories or keywords.

2.6    Environment Variables

LANG [73:2625] Additional semantics of this variable, if any, are implementation defined.

The operating system allows no additional semantics for this variable.

LC_COLLATE [74:2634] Additional semantics of this variable, if any, are implementation defined.

The operating system allows no additional semantics for this variable.

LC_CTYPE [74:2641] Additional semantics of this variable, if any, are implementation defined.

The operating system allows no additional semantics for this variable.

LC_MESSAGES [74:2647] Additional semantics of this variable, if any, are implementation defined.

The operating system allows no additional semantics for this variable.

LC_MONETARY [74:2653] Additional semantics of this variable, if any, are implementation defined.

The operating system allows no additional semantics for this variable.

LC_NUMERIC [74:2658] Additional semantics of this variable, if any, are implementation defined.

The operating system allows no additional semantics for this variable.

LC_TIME [74:2661] Additional semantics of this variable, if any, are implementation defined.

The operating system allows no additional semantics for this variable.

PATH [75:2697] If PATH is unset or is set to null, the path search is implementation defined.

If PATH is unset or is set to null, the operating system will use a default path of /bin:/usr/bin: (specifying /bin, /usr/bin, and the current directory in that order).

[76:2725] If the LANG environment variable is not set or is set to the empty string, the implementation-defined default locale shall be used.

If the LANG environment variable is not set or is set to the empty string, the operating system uses the POSIX locale as the default locale.

[76:2741] Additional criteria for determining a valid locale name are implementation defined.

The operating system uses no additional criteria to determine a valid locale name.

2.9    Dependencies on Other Standards

2.9.1    Features Inherited from POSIX.1

2.9.1.5    File Removal

[93:3419] When a directory that is the root directory or current working directory is removed, the effect is implementation defined.

When a directory that is the root directory or current working directory of a process is removed, that process will continue normally until completion with the exception that it can no longer access the non-existent directory, for example for reading or writing.

2.14    Terminal Characteristics

[114:4264] The implementation shall document which terminal types it supports and which of these features and utilities are not supported by each terminal.

The operating system supports the terminal types shown in Table 2-21.

Table 2-21: Terminal Types Supported

Manufacturer Terminal Type Features or Utilities Not Supported

AED aed512  
Ampex d80  
Amtek Business Mach abm80  
Amtek Business Mach tab132  
BitGraph bg1.25  
BitGraph bg2.0  
Ann Arbor aa4080  
Ann Arbor aaa-18  
Ann Arbor aaa-20  
Ann Arbor aaa-22  
Ann Arbor aaa-24  
Ann Arbor aaa-26  
Ann Arbor aaa-28  
Ann Arbor aaa-30  
Ann Arbor aaa-36  
Ann Arbor aaa-40  
Ann Arbor aaa-48  
Ann Arbor aaa-60  
AT386 console at386  
Beehive bh3m  
Beehive microb  
Beehive sb1  
Beehive sb2  
Beehive sbi  
Chromatics cg7900  
Computer Automation ca22851  
Concept c100  
Concept c108  
Concept oc100  
Consul a980  
Control Data cdc456  
Cybernex mdl110  
Cybernex xl83  
Data General cdi1203  
Data General d100  
Data General dg6053  
Datagraphix d132  
Datapoint dp3  
Datamedia dm1520  
Datamedia dm2500  
Datamedia dm3025  
Datamedia dm3045  
Datamedia dmdt80  
Compaq vt52  
Compaq vt100  
Compaq vt102  
Compaq vt125  
Compaq vt200  
Compaq vt220  
Compaq vt240  
Compaq vt241  
Compaq vt282  
Compaq vt300  
Compaq vt320  
Compaq vt330  
Compaq vt340  
Compaq vt341  
Compaq vt382  
Compaq vt383  
Compaq vt400  
Compaq vt420  
Compaq vt510  
Delta Data dd5000  
Diablo 1620  
Diablo 1640  
Diablo 5520  
Diablo agile  
Diablo aj830  
Diablo dtc300s  
Diablo qume5  
Diablo x1720  
Digilog 333  
Direct 800  
Envision env230  
Execuport ep40  
Execuport ep48  
Falco fal49  
Falco ts1  
Fluke f1720  
General Terminal 400  
General Terminal gt100  
Hazeltine h1000 cannot erase, cannot do vi
Hazeltine h1420 cannot erase
Hazeltine h1500 cannot erase
Hazeltine h1510 cannot erase
Hazeltine h1520 cannot erase
Hazeltine h2000  
Hazeltine esprit  
Heathkit (Zenith) h19  
Heathkit (Zenith) h89  
Heathkit (Zenith) altoh19  
Heathkit (Zenith) ztx11  
Hewlett Packard hp2621  
Hewlett Packard hp2622  
Hewlett Packard hp2623  
Hewlett Packard hp2626  
Hewlett Packard hp2640  
Hewlett Packard hp2645  
Hewlett Packard hp2648  
Homebrew bc  
Homebrew carlock  
Homebrew ex3000  
Homebrew nucterm  
Homebrew sexidy  
Homebrew smarterm  
Homebrew smartvid  
Homebrew ttyWilliams  
Homebrew ubell  
Homebrew uVAX-qdss  
Homebrew uVAX-exidy  
Homebrew uVAX-netx  
Homebrew xitex  
IBM 3101  
IBM 3151  
IBM 3161  
IBM 3162  
IBM 3163  
IBM 5081  
IBM 5151  
IBM 5154  
IBM 5550  
IBM 6153  
IBM 6154  
IBM 6155  
IBM hft-nam  
IBM hft-m  
IBM ibmaed  
IBM ibmc  
IBM ibmcx  
IBM ibmpc  
IBM ibmpcc  
IBM ibmx  
Intertec Data intertube2  
Intertec Data superbrain  
Kimtron abm85 vi `del' character does not work right
Lear Siegler (ADM) adm1  
Lear Siegler (ADM) adm2  
Lear Siegler (ADM) adm3  
Lear Siegler (ADM) adm5  
Lear Siegler (ADM) adm21  
Lear Siegler (ADM) adm31  
Lear Siegler (ADM) adm36  
Lear Siegler (ADM) adm42  
Liberty Electronics freedom100  
Liberty Electronics freedom110  
Liberty Electronics freedom200  
Microterm act4  
Microterm act5  
Microterm mime1  
Microterm mime2  
Microterm mime3  
Multiwriter mw2  
Omron 8025AG  
Perkin Elmer bantam  
Perkin Elmer fox  
Perkin Elmer owl  
PC Terminals apple  
PC Terminals beacon  
PC Terminals megatek  
PC Terminals microkit  
PC Terminals pc  
PC Terminals pccons  
PC Terminals sol1  
PC Terminals sol2  
PC Terminals sun1  
PC Terminals terak  
PC Terminals trs80  
PC Terminals unitrm18  
Plasma Panel plasma  
PMAX pmcons  
Ramtek ramtek6000  
Regent regent20  
Regent regent25  
Regent regent40  
Regent regent60  
Regent regent100  
Regent regent200  
Soroc iq120  
Soroc iq140  
Southwest Technical ct82  
Sun Microsystems sun-1  
Sun Microsystems sun-12  
Sun Microsystems sun-17  
Sun Microsystems sun-24  
Sun Microsystems sun-34  
Sun Microsystems sun-48  
Sun Microsystems sun-nic  
Sun Microsystems sun-s-e  
Sun Microsystems workstation console  
Synertek ktm380  
Tec Scope tec400  
Tec Scope tec500  
Tektronix ct8500  
Tektronix t500  
Tektronix tek4013  
Tektronix tek4014  
Tektronix tek4015  
Tektronix tek4023  
Tektronix tek4025  
Tektronix tek4105  
Tektronix tek4107  
Tektronix tek4112  
Tektronix tek4113  
Tektronix tek4114  
Tektronix tek4115  
Tektronix tek4125  
Tektronix tek4404  
Teleray t16  
Teleray t1061  
Teleray t3700  
Teleray t3800  
Teletec datascreen  
Teletype 4424  
Teletype ansi  
Teletype blit  
Teletype cbblit  
Teletype oblit  
Teletype blitlayer  
Teletype tty33  
Teletype tty37  
Teletype tty40  
Teletype tty43  
Televideo ims950  
Televideo tvi910  
Televideo tvi912  
Televideo tvi920  
Televideo tvi924  
Televideo tvi925  
Televideo tvi950  
Televideo tvipt  
Televideo ultima2  
Terminet terminet1200  
Texas Instruments ti700  
Texas Instruments ti745  
Texas Instruments ti800  
Texas Instruments ti931  
Viewpoint viewpoint  
Viewpoint screwpoint  
Virtual ansi  
Virtual minansi  
Virtual mransi  
Virtual 1line  
Virtual 1linepty  
Visual ovi300  
Visual vi200  
Visual vi300  
Visual vi550  
Volker-craig vc303 scrolls 2 lines at a time
Volker-craig vc404  
Volker-craig vc415  
Wyse wy30  
Wyse wy50  
Wyse wy100  
Wyse wy350  
Xterm xterm  
Xterm xterm-ap  
Xterm xterm-nc  
Xterm xterms  
Xterm xterms-ap  
Yterm yterm10 cannot do vi
Yterm yterm11  
Zentec zen30  

[114:4266] This implementation-defined list of terminals

\h'3m'-- Shall include at least one terminal type that is capable of supporting all of the standard utilities and all of their features, if the {POSIX2_CHAR_TERM} option is provided.

The VT100 terminal type supports all features of all standard utilities.

[114:4266] This implementation-defined list of terminals

\h'3m'-- Need not consist of an exhaustive list of terminal models when the implementor considers that some terminal types are used too infrequently to be listed.

The list of terminals provided in Table 2-21 shows all terminal types supported by the operating system.