Re: [Gumstix-users] c/c++ programming : char values ...?

[<jer...@gm...>]

Thanks a lot !
-fsigned-char works well for now !!! :)


2005/5/19, Florian Loitsch <gu...@fl...>:
>=20
> On Thursday 19 May 2005 16:17, David I S Mandala wrote:
> > The gumstix is treating the char as unsigned and the x86 is treating it
> > as signed. You made a very typical mistake of coding for cross
> > platforms, that being not specific enough and making an assumption what
> > the compiler is going to do. Either change your declaration line to
> > signed char or unsigned char in both tests and they will be the same.
> you could also pass the flag -fsigned-char to your arm-gcc (which is=20
> probably
> easier, than searching through all files).
> // florian
>=20
> >
> > On Thu, 2005-05-19 at 15:57 +0200, J=E9r=F4me Multrier wrote:
> > > Hello !
> > > I just found something strange :
> > > Following lines work differently on gumstix and my x86 :
> > > char c=3D-1;
> > > printf("char value : %d\n",(int)c);
> > >
> > > my gumstix says :
> > > char value : 255
> > >
> > > my computer says :
> > > char value : -1
> > >
> > > Doesn't anybody know where does this difference comes from ?
> > >
> > > Thanks,
> > > Jerome
> > >
> > >
> > > here are my compilers versions :
> > > ********************* for x86
> > > g++ -v
> > > Lecture des sp=E9cification =E0 partir de
> > > /usr/lib/gcc-lib/i486-linux/3.3.5/specs Configur=E9 avec:=20
> ../src/configure
> > > -v
> > > --enable-languages=3Dc,c++,java,f77,pascal,objc,ada,treelang
> > > --prefix=3D/usr --mandir=3D/usr/share/man --infodir=3D/usr/share/info
> > > --with-gxx-include-dir=3D/usr/include/c++/3.3 --enable-shared
> > > --enable-__cxa_atexit --with-system-zlib --enable-nls
> > > --without-included-gettext --enable-clocale=3Dgnu --enable-debug
> > > --enable-java-gc=3Dboehm --enable-java-awt=3Dxlib --enable-objc-gc
> > > i486-linux
> > > Mod=E8le de thread: posix
> > > version gcc 3.3.5 (Debian 1:3.3.5-12)
> > >
> > > ********************* for arm
> > > /.../build_arm_nofpu/staging_dir/bin/arm-linux-g++ -v
> > > Reading specs from
> > > /.../build_arm_nofpu/.../gcc/arm-linux-uclibc/3.4.2/specs Configured
> > > with: /.../toolchain_build_arm_nofpu/gcc-3.4.2/configure
> > > --prefix=3D/.../build_arm_nofpu/staging_dir --build=3Di386-pc-linux-g=
nu
> > > --host=3Di386-pc-linux-gnu --target=3Darm-linux-uclibc
> > > --enable-languages=3Dc,c++ --enable-shared --disable-__cxa_atexit
> > > --enable-target-optspace --with-gnu-ld --disable-nls --with-float=3Ds=
oft
> > > --enable-sjlj-exceptions
> > > Thread model: posix
> > > gcc version 3.4.2
> > >
> > >
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--=20
Jerome