[Monetdb-developers] Signed/unsigned and NULL

Fabian Groffen Fabian.Groffen at cwi.nl
Tue Oct 24 10:35:52 CEST 2006


Problem already solved, missed another warning in front.  Thanks anyway.

On 24-10-2006 10:33:48 +0200, Stefan Manegold wrote:
> Just try with both
> 
> void myfunc(unsigned char *s) {
> 
> and
> 
> void myfunc(signed char *s) {
> 
> and you find out, whether you compiler be default defines char as signed or
> unsigned (and whether your systems/compilers header files define NULL as
> signed or unsigend) ;-)
> 
> Stefan
> 
> 
> On Tue, Oct 24, 2006 at 10:16:11AM +0200, Fabian Groffen wrote:
> > I just figured that the following yields in a signed/unsigned warning:
> > 
> >  1  void myfunc(char *s) {
> >  2   if (s != NULL) {
> >  3      ...
> >  4    }
> >  5  }
> > 
> > The error occurs on line 2.  I cannot find the definition of NULL, but I
> > suspect it is defined like:
> > #define NULL 0
> > 
> > Obviously 0 is signed while s (pointer) is not.  Maybe we should use
> > #define NULL (char*)0
> > instead?
> > 
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> 
> -- 
> | Dr. Stefan Manegold | mailto:Stefan.Manegold at cwi.nl |
> | CWI,  P.O.Box 94079 | http://www.cwi.nl/~manegold/  |
> | 1090 GB Amsterdam   | Tel.: +31 (20) 592-4212       |
> | The Netherlands     | Fax : +31 (20) 592-4312       |
> 
> -------------------------------------------------------------------------
> Using Tomcat but need to do more? Need to support web services, security?
> Get stuff done quickly with pre-integrated technology to make your job easier
> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
> http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642
> _______________________________________________
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