C++11: is std::locale::empty() even a thing?

Question

Trying to compile some code from StackOverflow, basically, these lines:

std::wifstream wif(filename);
wif.imbue(std::locale(std::locale::empty(), new std::codecvt_utf8<wchar_t>));

GCC version: gcc (Ubuntu 5.4.0-6ubuntu1~16.04.4) 5.4.0

I get a compile error:

'empty' is not a member of 'std::locale'

And I agree with the compiler, checked with documentation like cppreference - there is no info about such thing. Header files as well do not show anything.

I wonder, if this is just me or the sample code from another topic...

Can it be a MSVC feature? (the sample code I used is from the question related to Windows)

https://msdn.microsoft.com/ru-ru/library/1w3527e2(v=VS.71).aspx — dan04, Jan 19 '17 at 23:11

score 3 · Accepted Answer · edited Jun 20 '20 at 09:12

3

This is a platform-specific extension to the locale class, and it used to be described in this MSVC documentation*:

In this implementation, you can also call the static member function:
static locale empty( );
to construct a locale object that has no facets. It is also a transparent locale; if the template functions has_facet and use_facet cannot find the requested facet in a transparent locale, they consult first the global locale and then, if that is transparent, the classic locale.

* the MSVC documentation link is outdated now, for best replacement see this documentation page instead

edited Jun 20 '20 at 09:12

Community

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answered Jan 21 '17 at 16:50

andrgolubev

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I guess the phrase *"In this implementation"* is key - it's a platform-specific extension rather that a standard member. – Toby Speight May 15 '17 at 11:17
@TobySpeight indeed, it is an extension provided by MSVC (I guess, in reality, it is only applicable to some of the versions) – andrgolubev May 17 '17 at 21:33
like has been dead. Updated version: https://learn.microsoft.com/en-us/cpp/standard-library/locale-class?view=vs-2019 – phuclv Oct 22 '19 at 06:32
@phuclv I guess you mean __the link__, thanks, will update – andrgolubev Oct 22 '19 at 22:34

score 0 · Answer 2 · answered Oct 06 '22 at 16:48

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Using std::locale() instead of std::locale:empty() worked for me.

answered Oct 06 '22 at 16:48

Alireza

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C++11: is std::locale::empty() even a thing?

2 Answers2

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