std::has_facet

 

C++

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本地化库

语言环境方面 Original: Locales and facets The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
locale
use_facet	has_facet
字符分类 Original: Character classification The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
isspace isblank （C++11） iscntrl isupper islower isalpha	isdigit ispunct isxdigit isalnum isprint isgraph
转换 Original: Conversions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
toupper tolower	wstring_convert （C++11） wbuffer_convert （C++11）
小面类的基类 Original: Facet category base classes The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
ctype_base codecvt_base messages_base	time_base money_base
小面类 Original: Facet categories The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
ctype ctype<char> codecvt collate messages time_get time_put	num_get num_put numpunct money_get money_put moneypunct
特定于语言环境的方面 Original: Locale-specific facets The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
ctype_byname ctype_byname<char> codecvt_byname messages_byname collate_byname	time_get_byname time_put_byname numpunct_byname moneypunct_byname
代码转换方面 Original: Code conversion facets The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
codecvt_utf8 （C++11） codecvt_utf16 （C++11）	codecvt_utf8_utf16 （C++11） codecvt_mode （C++11）
C语言环境 Original: C locale The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
setlocale localeconv lconv	LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME

 

Defined in header <locale>
template< class Facet > bool has_facet( const locale& loc );

检查如果语言环境loc实现的方面Facet

Original:

Checks if the locale loc implements the facet Facet.

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参数

loc

-

Locale对象来查询 Original: the locale object to query The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

返回值

返回true如果小Facet安装的语言环境中的loc，false否则.

Original:

Returns true if the facet Facet was installed in the locale loc, false otherwise.

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异常规范

noexcept specification:  

noexcept

  （C++11 起）

为例

#include <iostream>
#include <locale>
// minimal custom facet
struct myfacet : public std::locale::facet {
    static std::locale::id id;
};
std::locale::id myfacet::id;
int main()
{
    // loc is a "C" locale with myfacet added
    std::locale loc(std::locale::classic(), new myfacet);
    std::cout << std::boolalpha
              << "Can loc classify chars? "
              << std::has_facet<std::ctype<char>>(loc) << '\n'
              << "Can loc classify char32_t? "
              << std::has_facet<std::ctype<char32_t>>(loc) << '\n'
              << "Does loc implement myfacet? "
              << std::has_facet<myfacet>(loc) << '\n';
}

Output:

Can loc classify chars? true
Can loc classify char32_t? false
Does loc implement myfacet? true

另请参阅

locale	多态的文化差异方面的封装 Original: set of polymorphic facets that encapsulate cultural differences The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （类）
use_facet	得到的语言环境的一个方面 Original: obtains a facet from a locale The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. （函数模板）