Re: ddd/MString.h problems in 3.3 with Solaris C++ compiler, liberty install problems

[Andreas Zeller]

Hi!

bug-ddd@thewrittenword.com writes:

> ddd/MString.h has:
> 
> public:
>     // Constructors
>     MString(const char *text = "",
>             XmStringCharSet charset = MSTRING_DEFAULT_CHARSET):
>         _mstring(text ? XmStringCreateLtoR((char *)text, charset) : 0)
>     {
>         assert(OK());
>     }
> 
> #if 0
>     MString(char *text,
>             XmStringCharSet charset = MSTRING_DEFAULT_CHARSET):
>         _mstring(text ? XmStringCreateLtoR(text, charset) : 0)
>     {
>         assert(OK());
>     }
> #endif
> 
> The Sun C++ compiler (5.0 and 5.2) complains with:
>   CC -DHAVE_CONFIG_H -I. -I. -I. -I./.. -I/opt/TWWfsw/xpm/include
>   -I/usr/dt/include -I/usr/openwin/include
>   -I/opt/TWWfsw/readline4/include   -DNDEBUG -xs  -xO2 -xtarget=generic
>   -xarch=v8    -c ddd.C
>   "MString.h", line 57: Error: Formal argument text of type char* in
>   call to XmStringCreateLtoR(char*, char*) is being passed const char*.
> 
> Why was the constructor changed? Patch below to revert. Incidentally,
> neither G++ 2.95.2 nor IRIX C++ 7.3.1m and 7.3.1.2m complain.

String constants in C++ are now of type `const char[]', so I must care
about const correctness in DDD code.  The change was made to avoid
lots of warnings on compilers that already treat string constants as
read-only.  For GCC, this is (still) optional; try compiling with `gcc
-Wwrite-strings'.

In this particular case, the Sun C++ compiler is wrong: the `text'
argument to XmStringCreateLtoR(char*, char*) is explicitly casted to
`char *', so I cannot see what's wrong here.  If you find a way to
make both the Sun C++ compiler happy and not to generate any warnings
with `gcc -Wwrite-strings', I'll be happy to apply it.

Thanks and best wishes,

Andreas

-- 
Andreas Zeller     Universitaet Passau
                   http://www.fmi.uni-passau.de/st/staff/zeller/