Re: inline (Re: guile: going the way of DEATH)

[Gordon Matzigkeit <gord@trick.fig.org>]

Hi!

>>>>> Greg Badros writes:

 >> The biggie is the DBUG macro--multiple macros of the same name
 >> that differ only in their number of arguments is not allowed.

 GB> Hmmm... we protect that one with #ifdef __GNUC__, though.  From
 GB> scwm.h:

This code is not portable:

/* Not GNUC, so no varargs macros */
#  ifdef SCWM_DEBUG_MSGS
#    define DBUG(x,y) scwm_msg(DBG,x,y)
#    define DBUG(x,y,a) scwm_msg(DBG,x,y,a)
#    define DBUG(x,y,a,b) scwm_msg(DBG,x,y,a,b)
#    define DBUG(x,y,a,b,c) scwm_msg(DBG,x,y,a,b,c)
#    define DBUG(x,y,a,b,c,d) scwm_msg(DBG,x,y,a,b,c,d)
#    define DBUG(x,y,a,b,c,d,e) scwm_msg(DBG,x,y,a,b,c,d,e)
#  else
#    define DBUG(x,y)
#    define DBUG(x,y,a)
#    define DBUG(x,y,a,b)
#    define DBUG(x,y,a,b,c)
#    define DBUG(x,y,a,b,c,d)
#    define DBUG(x,y,a,b,c,d,e)
#  endif

There are C preprocessors that can't cope with macros that differ only
in their signatures.

The only portable way to do macros with variadic arguments is the
following:

#define DBUG(args) (scwm_msg args)

then use it with doubled-parentheses, such as:

DBUG ((x,y,a,b,c));
DBUG ((x,y));

-- 
 Gordon Matzigkeit <gord@fig.org> //\ I'm a FIG (http://www.fig.org/)
    Lovers of freedom, unite!     \// I use GNU (http://www.gnu.org/)

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