Fwd: variadic macro numerber of params

chedi toueiti chedi.toueiti@gmail.com
Mon Apr 26 20:58:00 GMT 2010


Hi,

I'm trying to write a macro to process a variable argument list but
need to know exactly the number of argument supplied.
Is there any way to do so with gcc ??

The only solution I found is based on a pseudo fixed limit :

#define PP_NARG(...)  PP_NARG_(__VA_ARGS__,PP_RSEQ_N())

#define PP_NARG_(...) PP_ARG_N(__VA_ARGS__)

#define PP_ARG_N( \
         _1, _2, _3, _4, _5, _6, _7, _8, _9,_10,
_11,_12,_13,_14,_15,_16,_17,_18,_19,_20,_21,_22,_23,_24,_25,_26,_27,_28,_29,_30,
_31,_32,_33,_34,_35,_36,_37,_38,_39,_40, \

         _41,_42,_43,_44,_45,_46,_47,_48,_49,_50,
_51,_52,_53,_54,_55,_56,_57,_58,_59,_60,_61,_62,_63,N,...) N

#define PP_RSEQ_N() \

         63,62,61,60,59,58,57,56,55,54,53,52,51,50,49,48,47,46,45,44,43,42,41,40,39,38,37,36,35,34,33,32,31,30,29,28,27,26,25,24,23,22,21,20,19,18,17,16,
\
         15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0



Regards,



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