Re: mbox compiler warning fix

[Andrew Lunn <andrew at lunn dot ch>]

> >Unfortunately, that does not work:
> >
> >/home/lunn/eCos/anoncvs-clean/packages/kernel/current/src/sync/mbox.cxx: 
> >In member function 'void* Cyg_Mbox::get()':
> >/home/lunn/eCos/anoncvs-clean/packages/kernel/current/src/sync/mbox.cxx:113: warning: 'used' attribute ignored
> >/home/lunn/eCos/anoncvs-clean/packages/kernel/current/src/sync/mbox.cxx:113: warning: 'p' may be used uninitialized in this
> >
> >when compiling:
> >
> >void *
> >Cyg_Mbox::get()
> >{
> >  void * CYGBLD_ATTRIB_USED p;
> >    if ( ! m.get( p ) )
> >        return NULL;
> >    return p;
> >}
> >
> >I also tried the CYGBLD_ATTRIB_USED in other positions on the line and
> >nothing works. 
> 
> UNUSED not USED. I don't know where __attribute__((used)) 
> (CYGBLD_ATTRIB_USED) comes from. It's not documented in the GCC manuals 
> I've seen (4.1.1 or 3.4.6, for example, at http://gcc.gnu.org/onlinedocs/).

Ah, O.K. 

Well, we don't have CYGBLD_ATTRIB_UNUSED in cyg_type.h. What we have is

# if !defined(CYGBLD_ATTRIB_USED)
#  if __GNUC_VERSION__ >= 30302
#   define CYGBLD_ATTRIB_USED __attribute__((used))
#  else
#   define CYGBLD_ATTRIB_USED __attribute__((unused))
#  endif
# endif

This tells the compiler that a variable is used, or at least it should
not complain about it not being used. Typically this is for #ifdef
out code, yet the variable declarations still exist. 

However the warning im getting is different. Its about passing an
uninitialised variable to a function. 

Is CYGBLD_ATTRIB_UNUSED something eCosCentric have added to there
private branch?

     Andrew