Re: libstdc++/5133: Problems with toupper

[Peter Schmid <schmid@snake.iap.physik.tu-darmstadt.de>]

The following reply was made to PR libstdc++/5133; it has been noted by GNATS.

From: Peter Schmid <schmid@snake.iap.physik.tu-darmstadt.de>
To: paolo@gcc.gnu.org, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org,
        nobody@gcc.gnu.org, paolo@gcc.gnu.org,
        schmid@snake.iap.physik.tu-darmstadt.de, gcc-gnats@gcc.gnu.org
Cc:  
Subject: Re: libstdc++/5133: Problems with toupper
Date: Mon, 17 Dec 2001 00:39:53 +0100 (CET)

 On 16 Dec 2001 paolo@gcc.gnu.org wrote:
 
 > Synopsis: Problems with toupper
 > 
 > Responsible-Changed-From-To: unassigned->paolo
 > Responsible-Changed-By: paolo
 > Responsible-Changed-When: Sun Dec 16 13:53:55 2001
 > Responsible-Changed-Why:
 >     Taking care of this.
 > State-Changed-From-To: open->feedback
 > State-Changed-By: paolo
 > State-Changed-When: Sun Dec 16 13:53:55 2001
 > State-Changed-Why:
 >     Hi Peter,
 >     
 >     in Josuttis, pp. 499 and 718 I find an explanation of what
 >     is happening with your testcase. In a nutshell, tolower and
 >     toupper are old C functions (you may use them through
 >     cctype) whereas std::toupper(c, loc) (and the corresponding
 >     tolower) are global functions of the C++ locales.
 >     Therefore, your testcase should be changed to:
 >     
 >     #include <string>
 >     #include <iostream> 
 >     #include <algorithm>
 >     #include <cctype>
 >     
 >     int main()
 >     {
 >         std::string s("Hallo");
 >         //std::transform (s.begin(), s.end(), s.begin(), std::tolower);
 >         //std::transform (s.begin(), s.end(), s.begin(), ::tolower);
 >         std::transform (s.begin(), s.end(), s.begin(), tolower);
 >         std::cout << "lowered: " << s << std::endl;
 >     }
 >     
 >     which indeed compiles and runs fine.
 >     
 >     Ok?
 >     
 >     Cheers,
 >     Paolo.
 >     
 >      
 > 
 > http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5133
 > 
 
 It is IMHO not ok. If you consider the following source tl.C, a stripped
 down version from string/iter1.C from Josuttis, cf. pages number
 497--499. Also cf. page number 720. 
 
 I believe that this source code is legal and according to Josuttis the
 <c*> headers inject the corresponding <*.h> functions into the std
 namespace. Therefore, I have no idea why this code, the call to std::tolower
 is rejected. Additionally, why does the code compile if the iostream
 header is removed?
 
 Peter Schmid 
 
 
 tl.C
 #include <string>
 #include <iostream> // does work, when this line is removed
 #include <algorithm>
 #include <cctype>
 
 using namespace std;
 
 int main()
 {
     string s("Hallo");
     transform (s.begin(), s.end(), s.begin(), tolower);
     transform (s.begin(), s.end(), s.begin(), ::tolower);
 }
 
 g++ -o tl tl.C -W -Wall
 tl.C: In function `int main()':
 tl.C:11: no matching function for call to `transform(
    std::__normal_iterator<char*, std::basic_string<char, 
    std::char_traits<char>, std::allocator<char> > >, 
    std::__normal_iterator<char*, std::basic_string<char, 
    std::char_traits<char>, std::allocator<char> > >, 
    std::__normal_iterator<char*, std::basic_string<char, 
    std::char_traits<char>, std::allocator<char> > >, <unknown type>)'