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