Re: Use of #if DEBUG in reent.h

[Christian Groessler <chris at groessler dot org>]

On 01/04/17 15:05, Eric Blake wrote:
> On 01/04/2017 04:14 AM, Freddie Chopin wrote:
> > Hi!
> >
> > Maybe it would be ok to change the offending line to:
> >
> > #if defined(DEBUG) && DEBUG != 0
> >
> > This way the old behaviour should be retained in most of the cases.
> > >From what I've read, if you add "-DDEBUG" to GCC flags, it is
> > equivalent to "-DDEBUG=1".
> Not by my experience.  There's a difference to being defined to the
> empty string (-DDEBUG on the command line corresponds to '#define DEBUG'
> in source) vs. an explicit string (-DDEBUG=1 corresponds to '#define
> DEBUG 1').


No.

$ gcc -dM -E - < /dev/null  | grep DEBUG
$ gcc -DDEBUG -dM -E - < /dev/null  | grep DEBUG
#define DEBUG 1
$


regards,
chris