How to convert string to wstring by means of STL and C++ headers only?

[Stuart Dootson]

std::ctype::widen[^]

[alabax]

that's the only ;)

[alabax]

like this: wstring s2w(const string &s) { size_t l=s.size()+1; const char *pc=s.c_str(); wchar_t *pw=new wchar_t[l]; locale loc(""); use_facet>(loc).widen(pc,pc+l-1,pw); return wstring(pw); } -- modified at 14:03 Wednesday 12th April, 2006

[Stuart Dootson]

Look s about right - proof of the pudding's in the testing, of course!

[alabax]

OMG! It's such a shame I did new without delete ;) GC is deep in my mind! wstring s2w(const string &s) { size_t l=s.size()+1; const char *pc=s.c_str(); wchar_t *pw=new wchar_t[l]; if (pw==0) throw; locale loc(""); use_facet>(loc).widen(pc,pc+l-1,pw); wstring ws(pw); delete [] pw; return ws; }

[Lost User]

You're not freeing the memory used by pw, unless I've missed something?

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The Rob Blog
Google Talk: robert.caldecott

[Lost User]

You could always use a vector instead. :)

vector<wchar_t> pw(l);
...
use_facet<ctype<wchar_t> >(loc).widen(pc,pc+l-1,&pw[0]);
wstring ws(&pw[0]);

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The Rob Blog
Google Talk: robert.caldecott

[Stuart Dootson]

As Robert says, you could use std::vector - or you could use boost::scoped_array<wchar_t>[^] instead of wchar_t

[toxcct]

yeah, that's what i see, so, why did you say "once again about it" ??? ;P

[alabax]

locale global_locale; wstring s2w(const string &s,const locale &loc=global_locale) { size_t l=s.length()+1; const char *pc=s.c_str(); wchar_t *pw=new wchar_t[l]; if (pw==0) throw; use_facet>(loc).widen(pc,pc+l-1,pw); pw[l-1]=L'\0'; wstring ws(pw); delete [] pw; return ws; }

[Nemanja Trifunovic]

Not exception safe ;) As others suggested, use std::vector or boost::scoped_array instead of new[]-delete[]

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[alabax]

Ok, here comes cute solution :) wstring s2w(const string &s,const locale &loc=global_locale) { size_t l=s.length(); vector pw(l+1); use_facet>(loc).widen(&s[0],&s[l],&pw[0]); wstring ws(&pw[0]); return ws; } widen does not append trailing L'\0'! The question is: does vector always initialize values to 0?

[alabax]

I mean questions like this appear every month on the newsgroups and message boards. =)

[Johann Gerell]

alabax wrote:

The question is: does vector always initialize values to 0?

Yes, the default value of a simple type using this vector ctor:

explicit vector(size_type count);

is 0. For classes, the default ctor is run, if no explicit value is provided in this vector ctor:

vector(size_type count, const T& value);

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