As you'll see, I went ahead and committed the patch you sent. After
reading about why gcc has done this and the ISO C++ standard, I think
I like your first patch the best. We will have to get some people to
try compiling with other C++ compilers and see if it breaks anything
(but my guess is it shouldn't). Even my Stroustrup book shows your
code to be good and it was the definitive on the language when most
compilers were designed.
David
Exactly. This means that this code is rejected
#include <iostream>
int main(void) {
cout << "hello" << endl;
return 0;
};
while these versions are legal
1)
#include <iostream>
int main(void) {
std::cout << "hello" << std::endl;
return 0;
};
2)
#include <iostream>
using namespace std;
int main(void) {
cout << "hello" << endl;
return 0;
};
3)
#include <iostream>
using std::cout;
using std::endl;
int main(void) {
cout << "hello" << endl;
return 0;
};
Version 1) is in the current patch. I think version 2)
is ill-advised, while version 3) could be a good compromise between
portability and namespace encapsulation. If you don't like solution 1)
I was thinking to add something like
dnl ----------------------------------------------------------------
dnl
dnl Check for std namespace
dnl
AC_LANG_CPLUSPLUS
AC_MSG_CHECKING([whether the C++ compiler allows to use namespace std])
AC_TRY_COMPILE([
#include <iostream>
using std::cout;
],[
cout << "a";
],[allow_std=yes],[allow_std=no])
if test $allow_std != no ; then
AC_DEFINE(USING_STD,1,[define if C++ compiler allows namespace std])
AC_MSG_RESULT([yes])
else
AC_MSG_RESULT([no])
fi
AC_LANG_C
dnl ----------------------------------------------------------------
in configure.ac
and then wrap everything:
#include <iostream>
#include <dxconfig.h>
if defined(USING_STD)
using std::cout;
using std::endl;
#endif
int main(void) {
cout << "hello" << endl;
return 0;
};
Do you think this solution could be ok?
Marco Morandini
--
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David L. Thompson Visualization and Imagery Solutions, Inc.
mailto:[EMAIL PROTECTED] 5515 Skyway Drive, Missoula, MT 59804
Phone : (406)257-8530
