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std::messages::get, do_get

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< cpp‎ | locale‎ | messages
Revision as of 08:27, 15 August 2013 by P12 (Talk | contribs)

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Defined in header <locale>
public:
string_type get( catalog cat, int set, int msgid, const string_type& dfault ) const;
(1)
protected:
virtual string_type do_get( catalog cat, int set, int msgid, const string_type& dfault ) const;
(2)

1) Public member function, calls the protected virtual member function do_get of the most derived class.

2) Obtains a message from the open message catalog cat using the values set, msgid and dfault in implementation-defined manner. If the expected message is not found in the catalog, returns a copy of dfault.

Contents

[edit] Parameters

cat - identifier of message catalog obtained from open() and not yet passed to close()
set - implementation-defined argument, message set in POSIX
msgid - implementation-defined argument, message id in POSIX
dfault - the string to look up in the catalog (if the catalog uses string look-up) and also the string to return in case of a failure

[edit] Return value

The message from the catalog or a copy of dfault if none was found.

[edit] Notes

On POSIX systems, this function call usually translates to a call to catgets(), and the parameters set, msgid, and dfault are passed to catgets() as-is. In GNU libstdc++, this function ignores set and msgid and simply calls GNU gettext(dfault) in the required locale.

[edit] 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);
}

Output:

"No match" in German: Keine Übereinstimmung
"Memory exhausted" in German: Speicher erschöpft

[edit] See also