std::messages<CharT>::open, std::messages<CharT>::do_open
From cppreference.com
Defined in header <locale>
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public
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catalog open( const std::string & name, const std::locale & loc ) const ; |
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protected
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virtual catalog do_open( const std::string & name, const std::locale & loc ) const ; |
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1) Public member function, calls the protected virtual member function
do_open of the most derived class.
2) Obtains a value of type
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 |
Return value
The non-negative value of type catalog that can be used with get() and close()
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.
Run this code
#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