In an earlier and a different posting, I express my concern about MS-Windows' std::string/locales, what is the point of wstring, I asked, if at the end there is no reliable uft-8/16/32 support for. them. The best thing to do is to use boost's or some other 3rd party, if true utf support is needed. towupper is no different than toupper when it comes to letters like á or ñ. I you know if a way to handle them, specially the letter LL and its lowercase counterpart when arranged in SIAO list (sort-in-alphabetical-order) please do let me know.
Thanks in advance. -----Original Message----- From: Martin Sebor Sent: Wednesday, July 1, 2015 11:17 AM To: [email protected] ; Riot ; [email protected] Cc: gcc-help Mailing List Subject: Re: [Mingw-w64-public] toUpper() On 07/01/2015 06:02 AM, [email protected] wrote: > std::wstring source(L"Hello World"); > std::wstring destination; > destination.resize(source.size()); > std::transform (source.begin(), source.end(), destination.begin(), > (int(*)(int))std::toupper); > > The above code is what did the trick, do not ask how, I am still > digesting it. However, any suggestions would be very much appreciated This solved problem (1) below but doesn't work correctly or portably because of the second problem I described in my first response. std::toupper(int) is defined for narrow characters in the range [0, UCHAR_MAX] plus EOF. The function has undefined behavior for characters outside that range (i.e., all wchar_t greater than UCHAR_MAX). I don't know what will happen on Windows(*) but on Linux, I can see the program doesn't work correctly for the Latin Extended Additional block of characters (the first one I noticed). For instance, running the attached modified version of the program in a UTF-8 locale such as en_US.utf8 to convert U+1EBD (LATIN SMALL LETTER E WITH TILDE) to its uppercase form (U+1EBC) prints: U+1EBD U+1EBC U+1EBD when the expected output is: U+1EBD U+1EBC U+1EBC If you want to use transform with wide characters, you need to use towupper (declared in <wctype.h>). Martin [*] I vaguely recall toupper and friends aborting on Windows when passed an out-of-range argument but I'm not 100% sure. > > -----Original Message----- From: Martin Sebor > Sent: Tuesday, June 30, 2015 10:01 PM > To: Riot ; [email protected] > Cc: gcc-help Mailing List > Subject: Re: [Mingw-w64-public] toUpper() > > On 06/30/2015 05:24 PM, Riot wrote: >> #include <algorithm> >> #include <string> >> >> std::string str = "Hello World"; >> std::transform(str.begin(), str.end(), str.begin(), std::toupper); > > Please note this code is subtly incorrect for two reasons. > There are two overloads of std::toupper: > > 1) int toupper(int) declared in <ctype.h> (and the equivalent > std::toupper in <cctype>) > 2) template <class T> charT std::toupper(T, const locale&) > in <locale> > > Without the right #include directive, the above may or may > not resolve to "the right" function (which depends on what > declarations the two headers bring into scope). > > When it resolves to (2) it will fail to compile. > > When it resolves to (1), it will do the wrong thing (have > undefined behavior) at runtime when char is a signed type > and the argument is negative (because (1) is only defined > for values between -1 and UCHAR_MAX). > > But the question is about converting std::wstring to upper > case and the above uses a narrow string. For wstring, the > std::ctype<wchar_t>::toupper() function or its convenience > non-member template function can be used. > >> See also: http://www.cplusplus.com/reference/locale/toupper/ > > This is one possible way to do it. Another approach is along > these lines: > > std::locale loc (...); > std::wstring wstr = L"..."; > const std::ctype<wchar_t> &ct = > std::use_facet<std::ctype<wchar_t> >(loc); > ct.toupper (&wstr[0], &wstr[0] + wstr.size()); > > Martin > >> >> This may also help in future: http://lmgtfy.com/?q=c%2B%2B+toupper >> >> -Riot >> >> On 30 June 2015 at 23:58, <[email protected]> wrote: >>> I would like to write a function to capitalize letters, say... >>> std::wstring toUpper(const std::wstring wstr){ >>> for ( auto it = wstr.begin(); it != wstr.end(); ++it){ >>> global_wapstr.append(std::towupper(&it)); >>> >>> } >>> } >>> >>> This doesn’t work, but doesn’t the standard already have something like >>> std::wstring::toUpper(...)? >>> >>> Thanks in advance >>> >>> >>> --- >>> This email has been checked for viruses by Avast antivirus software. >>> http://www.avast.com >>> >>> >>> ------------------------------------------------------------------------------ >>> >>> Don't Limit Your Business. 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