std::messages<CharT>:: open, std::messages<CharT>:: do_open
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Defined in header
<locale>
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||
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public
:
catalog open ( const std:: basic_string < char > & name, const std:: locale & loc ) const ; |
(1) | |
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protected
:
virtual catalog do_open ( const std:: basic_string < char > & name, const std:: locale & loc ) const ; |
(2) | |
do_open
of the most derived class.
catalog
(inherited from
std::messages_base
), which can be passed to
get()
to retrieve messages from the message catalog named by
name
. This value is usable until passed to
close()
.
Parameters
| name | - | name of the message catalog to open |
| loc | - | a locale object that provides additional facets that may be required to read messages from the catalog, such as std::codecvt to perform wide/multibyte conversions |
Return value
The non-negative value of type
catalog
that can be used with
get()
and
close()
. Returns a negative value if the catalog could not be opened.
Notes
On POSIX systems, this function call usually translates to a call to
catopen()
. In GNU libstdc++, it calls
textdomain
.
The actual catalog location is implementation-defined: for the catalog
"sed"
(message catalogs installed with the Unix utility
'sed'
) in German locale, for example, the file opened by this function call may be
/usr/lib/nls/msg/de_DE/sed.cat
,
/usr/lib/locale/de_DE/LC_MESSAGES/sed.cat
, or
/usr/share/locale/de/LC_MESSAGES/sed.mo
.
Example
The following example demonstrated retrieval of messages: on a typical GNU/Linux system it reads from
/usr/share/locale/de/LC_MESSAGES/sed.mo
.
#include <iostream> #include <locale> int main() { std::locale loc("de_DE.utf8"); std::cout.imbue(loc); auto& facet = std::use_facet<std::messages<char>>(loc); auto cat = facet.open("sed", loc); if (cat < 0) std::cout << "Could not open german \"sed\" message catalog\n"; else std::cout << "\"No match\" in German: " << facet.get(cat, 0, 0, "No match") << '\n' << "\"Memory exhausted\" in German: " << facet.get(cat, 0, 0, "Memory exhausted") << '\n'; facet.close(cat); }
Possible output:
"No match" in German: Keine Übereinstimmung "Memory exhausted" in German: Speicher erschöpft