...making Linux just a little more fun!
[ In reference to "Tips on Using Unicode with C/C++" in LG#147 ]
Jimmy O'Regan [joregan at gmail.com]
I was reminded of Ren?'s article while trying to get Apertium to compile with Cygwin, because Cygwin lacks wide string support in g++. I tried to find a canned piece of m4, to give a warning about this at configure time instead of compile time, but, alas, I couldn't find anything and had to write something myself.
Does anyone know enough about configure etc. to find any obvious problems with this?
# Check for wide strings
AC_DEFUN([AC_CXX_WSTRING],[
AC_CACHE_CHECK(whether the compiler supports wide strings,
ac_cv_cxx_wstring,
[AC_LANG_SAVE
AC_LANG_CPLUSPLUS
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <string>]],[[
std::wstring test = L"test";
int main () {}
]])],
[ac_cv_cxx_wstring=yes], [ac_cv_cxx_wstring=no])
AC_LANG_RESTORE
])
])
AC_CXX_WSTRING
if test "$ac_cv_cxx_wstring" = no
then
AC_MSG_ERROR([Missing wide string support])
fi
René Pfeiffer [lynx at luchs.at]
On Mar 20, 2008 at 0241 +0000, Jimmy O'Regan appeared and said:
> [...] > Does anyone know enough about configure etc. to find any obvious > problems with this? >=20 > ``` > # Check for wide strings > AC_DEFUN([AC_CXX_WSTRING],[ > AC_CACHE_CHECK(whether the compiler supports wide strings, > ac_cv_cxx_wstring, [...]
Hm, do you have the output in config.log at hand? I am not well fluent in autoconf. You can also send me the configure script and I'll run it (on non-Cygwin though) to see what tests it checks.
Best, René.
Jimmy O'Regan [joregan at gmail.com]
On 20/03/2008, René Pfeiffer <lynx@luchs.at> wrote:
> On Mar 20, 2008 at 0241 +0000, Jimmy O'Regan appeared and said: > > [...] > > > Does anyone know enough about configure etc. to find any obvious > > problems with this? > > > > ``` > > # Check for wide strings > > AC_DEFUN([AC_CXX_WSTRING],[ > > AC_CACHE_CHECK(whether the compiler supports wide strings, > > > ac_cv_cxx_wstring, [...] > > Hm, do you have the output in config.log at hand? I am not well fluent > in autoconf. You can also send me the configure script and I'll run it > (on non-Cygwin though) to see what tests it checks.
Well, thanks to your mention of config.log, I found one error myself - I misunderstood how AC_COMPILE_IFELSE works:
configure:3635: checking whether the compiler supports wide strings
configure:3671: g++ -c -g -O2 conftest.cpp >&5
conftest.cpp: In function `int main()':
conftest.cpp:14: error: `wstring' is not a member of `std'
conftest.cpp:14: error: expected `;' before "test"
conftest.cpp:15: error: expected primary-expression before "int"
conftest.cpp:15: error: expected `;' before "int"
configure:3677: $? =3D 1
configure: failed program was:
| /* confdefs.h. */
| #define PACKAGE_NAME ""
| #define PACKAGE_TARNAME ""
| #define PACKAGE_VERSION ""
| #define PACKAGE_STRING ""
| #define PACKAGE_BUGREPORT ""
| #define STDC_HEADERS 1
| /* end confdefs.h. */
| #include <string>
| int
| main ()
| {
|
| std::wstring test =3D L"test";
| int main () {}
|
| ;
| return 0;
| }
configure:3699: result: no
configure:3705: error: Missing wide string support
so, having removed the offending 'main () {}' line, it seems to fail for the right reasons:
configure:3635: checking whether the compiler supports wide strings
configure:3670: g++ -c -g -O2 conftest.cpp >&5
conftest.cpp: In function `int main()':
conftest.cpp:14: error: `wstring' is not a member of `std'
conftest.cpp:14: error: expected `;' before "test"
configure:3676: $? =3D 1
configure: failed program was:
| /* confdefs.h. */
| #define PACKAGE_NAME ""
| #define PACKAGE_TARNAME ""
| #define PACKAGE_VERSION ""
| #define PACKAGE_STRING ""
| #define PACKAGE_BUGREPORT ""
| #define STDC_HEADERS 1
| /* end confdefs.h. */
| #include <string>
| int
| main ()
| {
|
| std::wstring test =3D L"test";
|
| ;
| return 0;
| }
configure:3698: result: no
configure:3704: error: Missing wide string support
I've attached the whole log, and the dummy configure.in I used to test it.