W3cubDocs

/C++

std::locale::combine

Defined in header <locale>
template< class Facet >
locale combine( const locale& other ) const;

Constructs a locale object which is a copy of *this except for the facet of type Facet, which is copied from other.

The program is ill-formed if Facet is not a facet or it is a volatile-qualified facet.

Return value

The new, nameless, locale.

Exceptions

std::runtime_error if other does not implement Facet.

Example

#include <iostream>
#include <locale>
 
int main()
{
    const double number = 1000.25;
    std::cout << "\"C\" locale: " << number << '\n';
    std::locale loc = std::locale()
        .combine<std::numpunct<char>>(std::locale("en_US.UTF8"));
    std::cout.imbue(loc);
    std::cout << "\"C\" locale with en_US numpunct: " << number << '\n';
}

Output:

"C" locale: 1000.25
"C" locale with en_US numpunct: 1,000.25

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 14 C++98 locale::combine was non-const made const
LWG 436 C++98 it was unclear whether Facet can be cv-qualified it can be const-qualified, but not volatile-qualified

See also

constructs a new locale
(public member function)

© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/locale/locale/combine