From: G.Filippi
                                                           Date: 31 Jul 1999

		  ******** PRELIMINARY **********


             VLT-SW-OCT99 - EGCS 2.91 PORTABILITY GUIDELINES
             ===============================================



Egcs 2.91 presents a lot of differences to the previously used
version gcc2.7.2.2, expecially in the C++ area. Please refer to the
egcs Release Notes for more.

In the VLTSW code, the following differences have been noticed:

 - new warnings 

 - (HP implementation) all the methods must be in the same file
   Modules oslx, book, acc restructured in such a way that 
   the source files (one for each method) are included in the main.

 - to replace in ic0SERVER.h

             evhCB_COMPL_STAT GeneralCmdCB(msgMESSAGE &msg, void *udata);
   with 

     virtual evhCB_COMPL_STAT GeneralCmdCB(msgMESSAGE &msg, void *udata);

   to avoid linker problems.


 - the constructs '(<type>)0' or '(<type>)NULL' have to be replaced with
   just 'NULL'

 - (HP only) -ldce is required (vltMakefile takes care of it)

 - As of 2.8.0, libg++ has been split into libstdc++ and libg++,
   the latter not provide in 2.9*. Only libstdc++ should be used instead.




             VLT-SW-OCT99 - GCC 2.95 PORTABILITY GUIDELINES
             ===============================================

                                                           From: P.Sivera
                                                           Date: 1 Dec 1999


 - Each time the following compilation error appears (here an example 
   with acc module) :

accServer.C:91:
 no matches converting function `accDatabaseQueryCB'
 to type `evhCB_COMPL_STAT (fndOBJECT::*)(const msgRAW_MESSAGE &, void *)'
../include/accServer.h:40: candidates are:
 evhCB_COMPL_STAT accSERVER::accDatabaseQueryCB(msgMESSAGE &, void *)

   to fix the error it is enough to transform line 91 from:

cb.Proc((evhCB_METHOD)accDatabaseQueryCB));

   to:

cb.Proc((evhCB_METHOD)&accSERVER::accDatabaseQueryCB));


 - the same for the following error (here an example with evh module) :

../include/evhCOMMAND.icc:166:
 taking the address of a non-static member function
../include/evhCOMMAND.icc:166: 
 to form a pointer to member function, say `&evhCOMMAND::_TimeoutCB'

   In this case, transform line 166 from:

.Proc((evhCB_METHOD)&_TimeoutCB);

   to:

.Proc((evhCB_METHOD)&evhCOMMAND::_TimeoutCB);


REMARK: The second type of error becomes a warning when the flag 

               -fpermissive 

        is used in the vltMakefile.

 - Some warnings have been turned on at vltMakefile level. 
   Here follows a list of this warnings:

REMARK: for the external distribution, the vltMakefile 
        has still NO warnings.

                       -Wall                  
                       -Wundef                
                       -W                     
                       -Wshadow               
                       -Wpointer-arith        
                       -Wcast-qual            
                       -Wcast-align           
                       -Wwrite-strings        
                       -Wstrict-prototypes    
                       -Wmissing-prototypes   
                       -Wmissing-declarations

and for LCU code:

                       -Wall                  
                       -W                     
                       -Wshadow               
                       -Wpointer-arith        
                       -Wcast-qual            
                       -Wcast-align           
                       -Wwrite-strings        
                       -Wconversion           
                       -Wmissing-prototypes   
                       -Wmissing-declarations 

REMARK: if you want to turn these warnings off, you have to set 
        the environment varable 
           MAKE_NO_WARNINGS
        to ON


Here there are some suggestions to help you fix these warnings, 
as well as some practical examples:

1) docExPc.c:58: 
   warning: initialization discards qualifiers from pointer target type

Substitute the two following lines:

static char *rcsId="@(#) $Id: OCT99_RelNotes.GNU.port,v 1.139 2000/06/20 17:59:49 vltsccm Exp $";
static void *use_rcsId = ((void)&use_rcsId,(void *) &rcsId);

with the following (note the "const" declaration):

static const char *rcsId="@(#) $Id: OCT99_RelNotes.GNU.port,v 1.139 2000/06/20 17:59:49 vltsccm Exp $";
static const void *use_rcsId = ((const void)&use_rcsId,(const void *) &rcsId);

2)   ../include/alrmClassdef.h:31: 
   warning: function declaration isn't a prototype

    unsigned short ((*usf)());

    Must now have void argument:   unsigned short ((*usf)(void));

3) 
ibacLog.c:296: warning: 
passing arg 2 of `logData' with different width due to prototype
ibacLog.c:382: warning: 
passing arg 7 of `dbWriteSymbolic' with different width due to prototype
ibacLog.c:382: warning: 
passing arg 8 of `dbWriteSymbolic' with different width due to prototype
ibacErr.c:216: warning: 
passing arg 3 of `errAdd_v' with different width due to prototype

In this case, substitute all the following parameter types:

vltINT8
vltINT16

with:

vltINT32



4) Two similar warnings:

oslxALIAS.C:168: warning: 
declaration of `merge' shadows global declaration

and

oslxALIAS.C:176: warning: 
declaration of `i' shadows a member of `this'
  
In the first case, rename the "merge" variable.
In the second case, rename either the member of the class, 
or the parameter.

Suggestion: as using the same name for both the member and the 
            parameter is often clearer and to avoid finding out 
            a lot of different names, it could be a good compromise 
            to add an "underscore" (_) at the end of the name of 
            each class member. 

5)
/vlt/OCT99/include/eccsErr.icc: 
In method `const class eccsERROR_CLASS & eccsERROR_CLASS::ErrReset() const':
/vlt/OCT99/include/eccsErr.icc:37: warning: 
cast discards qualifiers from pointer target type

In general, this occurs when you cast a constant pointer into a non-constant
pointer type. You have to replace with the right cast, as shown in the following example:

Replace :

inline const eccsERROR_CLASS 
                 &eccsERROR_CLASS::ErrStatus(const ccsCOMPL_STAT s) const
{
    ((eccsERROR_CLASS*)this)->status = s;
    return *this;
}

With:

inline const eccsERROR_CLASS 
                 &eccsERROR_CLASS::ErrStatus(const ccsCOMPL_STAT s) const
{
    ((const eccsERROR_CLASS*)this)->status = s;
    return *this;
}
                                ___oOo___