Re: isspace

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Thu, 28 Jan 2010 14:46:14 -0800 (PST)
Message-ID:
<3ff05e6f-7d86-479d-af71-f924aaba92c4@k5g2000yqf.googlegroups.com>
On 28 Jan, 21:25, gervaz <ger...@gmail.com> wrote:

On Jan 28, 9:40 pm, Paavo Helde <myfirstn...@osa.pri.ee> wrote:

gervaz <ger...@gmail.com> wrote in news:198ffd0f-8a21-4d23-802f-
cf0f0fee0...@o28g2000yqh.googlegroups.com:

Hi all, is there a C++ function similar to isspace that
can handle w_chars? Does the regex library handles
w_chars?


Yes, there is a template function declared in <locale> and
named std::isspace, curiously enough.

There is no regex librar in the official C++ standard yet I
think. The Boost regex library is fully templated and ought
to support wchar_t as well, but I have not tried this.
According to Boost documentation one needs a separate ICU
library for full Unicode support though.


Well, take a look at my snippet:

std::ifstream infile(argv[1]);

std::string s;

while (getline(infile, s))
{
    s.erase(std::remove_if(s.begin(), s.end(), std::isspace), s.end
());
    std::cout << s;
}

Using locale on VC++2008 I've got an error reporting that
std::isspace expects 2 arguments,


That's because std::isspace requires two arguments, the
character to be tested, and the locale.

and still I don't know if the file contains unicode characters
can be correctly handles.


The functions in <locale> are pretty useless, since they only
handle single byte characters. The "approved" solution is to
read into a wstring using wifstream (embedded with the
appropriate locale), and use isspace (again with the appropriate
locale) on the wchar_t in the wstring.

--
James Kanze

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