The gettext(), dgettext(), and dcgettext() functions attempt to retrieve a target string based on the specified msgid argument within the context of a specific domain and the current locale. The length of strings returned by gettext(), dgettext(), and dcgettext() is undetermined until the function is called. The msgid argument is a null-terminated string.

The ngettext(), dngettext(), and dcngettext() functions are equivalent to gettext(), dgettext(), and dcgettext(), respectively, except for the handling of plural forms. These functions work only with GNU-compatible message catalogues. The ngettext(), dngettext(), and dcngettext() functions search for the message string using the msgid1 argument as the key and the n argument to determine the plural form. If no message catalogues are found, msgid1 is returned if n == 1, otherwise msgid2 is returned.

The NLSPATH environment variable (see environ(5)) is searched first for the location of the LC_MESSAGES catalogue. The setting of the LC_MESSAGES category of the current locale determines the locale used by gettext() and dgettext() for string retrieval. The category argument determines the locale used by dcgettext(). If NLSPATH is not defined and the current locale is "C", gettext(), dgettext(), and dcgettext() simply return the message string that was passed. In a locale other than "C", if NLSPATH is not defined or if a message catalogue is not found in any of the components specified by NLSPATH, the routines search for the message catalogue using the scheme described in the following paragraph.

The LANGUAGE environment variable is examined to determine the GNU-compatible message catalogues to be used. The value of LANGUAGE is a list of locale names separated by a colon (':') character. If LANGUAGE is defined, each locale name is tried in the specified order and if a GNU-compatible message catalogue is found, the message is returned. If a GNU-compatible message catalogue is found but failed to find a corresponding msgid, the msgid string is return. If LANGUAGE is not defined or if a Solaris message catalogue is found or no GNU-compatible message catalogue is found in processing LANGUAGE, the pathname used to locate the message catalogue is dirname/locale/category/domainname.mo, where dirname is the directory specified by bindtextdomain(), locale is a locale name, and category is either LC_MESSAGES if gettext(), dgettext(), ngettext(), or dngettext() is called, or LC_XXX where the name is the same as the locale category name specified by the category argument to dcgettext() or dcngettext().

For gettext() and ngettext(), the domain used is set by the last valid call to textdomain(). If a valid call to textdomain() has not been made, the default domain (called messages) is used.

For dgettext(), dcgettext(), dngettext(), and dcngettext(), the domain used is specified by the domainname argument. The domainname argument is equivalent in syntax and meaning to the domainname argument to textdomain(), except that the selection of the domain is valid only for the duration of the dgettext(), dcgettext(), dngettext(), or dcngettext() function call.

The textdomain() function sets or queries the name of the current domain of the active LC_MESSAGES locale category. The domainname argument is a null-terminated string that can contain only the characters allowed in legal filenames.

The domainname argument is the unique name of a domain on the system. If there are multiple versions of the same domain on one system, namespace collisions can be avoided by using bindtextdomain(). If textdomain() is not called, a default domain is selected. The setting of domain made by the last valid call to textdomain() remains valid across subsequent calls to setlocale(3C), and gettext().

The domainname argument is applied to the currently active LC_MESSAGES locale.

The current setting of the domain can be queried without affecting the current state of the domain by calling textdomain() with domainname set to the null pointer. Calling textdomain() with a domainname argument of a null string sets the domain to the default domain (messages).

The bindtextdomain() function binds the path predicate for a message domain domainname to the value contained in dirname. If domainname is a non-empty string and has not been bound previously, bindtextdomain() binds domainname with dirname.

If domainname is a non-empty string and has been bound previously, bindtextdomain() replaces the old binding with dirname. The dirname argument can be an absolute or relative pathname being resolved when gettext(), dgettext(), or dcgettext() are called. If domainname is a null pointer or an empty string, bindtextdomain() returns NULL. User defined domain names cannot begin with the string SYS_. Domain names beginning with this string are reserved for system use.

The bind_textdomain_codeset() function can be used to specify the output codeset for message catalogues for domain domainname. The codeset argument must be a valid codeset name that can be used for the iconv_open(3C) function, or a null pointer. If the codeset argument is the null pointer, bind_textdomain_codeset() returns the currently selected codeset for the domain with the name domainname. It returns a null pointer if a codeset has not yet been selected. The bind_textdomain_codeset() function can be used multiple times. If used multiple times with the same domainname argument, the later call overrides the settings made by the earlier one. The bind_textdomain_codeset() function returns a pointer to a string containing the name of the selected codeset. The string is allocated internally in the function and must not be changed by the user.

The gettext(), dgettext(), and dcgettext() functions return the message string if the search succeeds. Otherwise they return the msgid string.

The ngettext(), dngettext(), and dcngettext() functions return the message string if the search succeeds. If the search fails, msgid1 is returned if n == 1. Otherwise msgid2 is returned.

The individual bytes of the string returned by gettext(), dgettext(), dcgettext(), ngettext(), dngettext(), or dcngettext() can contain any value other than NULL. If msgid is a null pointer, the return value is undefined. The string returned must not be modified by the program, and can be invalidated by a subsequent call to gettext(), dgettext(), dcgettext(), ngettext(), dngettext(), dcngettext(), or setlocale(3C). If the domainname argument to dgettext(),dcgettext(), dngettext(), or dcngettext() is a null pointer, the the domain currently bound by textdomain() is used.

The normal return value from textdomain() is a pointer to a string containing the current setting of the domain. If domainname is a null pointer, textdomain() returns a pointer to the string containing the current domain. If textdomain() was not previously called and domainname is a null string, the name of the default domain is returned. The name of the default domain is messages. If textdomain() fails, a null pointer is returned.

The return value from bindtextdomain() is a null-terminated string containing dirname or the directory binding associated with domainname if dirname is NULL. If no binding is found, the default return value is /usr/lib/locale. If domainname is a null pointer or an empty string, bindtextdomain() takes no action and returns a null pointer. The string returned must not be modified by the caller. If bindtextdomain() fails, a null pointer is returned.

These functions impose no limit on message length. However, a text domainname is limited to TEXTDOMAINMAX (256) bytes.

The gettext(), dgettext(), dcgettext(), ngettext(), dngettext(), dcngettext(), textdomain(), and bindtextdomain() functions can be used safely in multithreaded applications, as long as setlocale(3C) is not being called to change the locale.

The gettext(), dgettext(), dcgettext(), textdomain(), and bindtextdomain() functions work with both Solaris message catalogues and GNU-compatible message catalogues. The ngettext(), dngettext(), dcngettext(), and bind_textdomain_codeset() functions work only with GNU-compatible message catalogues. See msgfmt(1) for information about Solaris message catalogues and GNU-compatible message catalogues.

/usr/lib/locale

default path predicate for message domain files

/usr/lib/locale/locale/LC_MESSAGES/domainname.mo

system default location for file containing messages for language locale and domainname

/usr/lib/locale/locale/LC_XXX/domainname.mo

system default location for file containing messages for language locale and domainname for dcgettext() calls where LC_XXX is LC_CTYPE, LC_NUMERIC, LC_TIME, LC_COLLATE, LC_MONETARY, or LC_MESSAGES

dirname/locale/LC_MESSAGES/domainname.mo

location for file containing messages for domain domainname and path predicate dirname after a successful call to bindtextdomain()

dirname/locale/LC_XXX/domainname.mo

location for files containing messages for domain domainname, language locale, and path predicate dirname after a successful call to bindtextdomain() for dcgettext() calls where LC_XXX is one of LC_CTYPE, LC_NUMERIC, LC_TIME, LC_COLLATE, LC_MONETARY, or LC_MESSAGES

See attributes(5) for descriptions of the following attributes:

msgfmt(1), xgettext(1), iconv_open(3C), setlocale(3C), attributes(5), environ(5)