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### 771. Impossible throws clause in [string.conversions]

Section: 21.3.5 [string.conversions] Status: CD1 Submitter: Daniel Krügler Opened: 2008-01-13 Last modified: 2016-01-28

Priority: Not Prioritized

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Discussion:

The new `to_string` and `to_wstring` functions described in 21.3.5 [string.conversions] have throws clauses (paragraphs 8 and 16) which say:

> Throws: nothing

Since all overloads return either a `std::string` or a `std::wstring` by value this throws clause is impossible to realize in general, since the `basic_string` constructors can fail due to out-of-memory conditions. Either these throws clauses should be removed or should be more detailled like:

> Throws: Nothing if the string construction throws nothing

Further there is an editorial issue in p. 14: All three `to_wstring` overloads return a `string`, which should be `wstring` instead (The header `<string>` synopsis of 21.3 [string.classes] is correct in this regard).

Proposed resolution:

In 21.3.5 [string.conversions], remove the paragraphs 8 and 16.

>     string to_string(long long val);
>     string to_string(unsigned long long val);
>     string to_string(long double val);

> > Throws: nothing

>     wstring to_wstring(long long val);
>     wstring to_wstring(unsigned long long val);
>     wstring to_wstring(long double val);

> > Throws: nothing