Created
June 27, 2018 19:15
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https://groups.google.com/forum/#!msg/comp.std.c/d-6Mj5Lko_s/5R6bMWTEbzQJ | |
/* The PP_NARG macro returns the number of arguments that have been | |
* passed to it. | |
*/ | |
#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 | |
/* Some test cases */ | |
PP_NARG(A) -> 1 | |
PP_NARG(A,B) -> 2 | |
PP_NARG(A,B,C) -> 3 | |
PP_NARG(A,B,C,D) -> 4 | |
PP_NARG(A,B,C,D,E) -> 5 | |
PP_NARG(1,2,3,4,5,6,7,8,9,0, | |
1,2,3,4,5,6,7,8,9,0, | |
1,2,3,4,5,6,7,8,9,0, | |
1,2,3,4,5,6,7,8,9,0, | |
1,2,3,4,5,6,7,8,9,0, | |
1,2,3,4,5,6,7,8,9,0, | |
1,2,3) -> 63 |
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Is there anyway to account for anyone passing something like: PP_NARG((thing){value1, vlaue2})
I guess it's not possible with this as that usage of , would split the arguments to the macro am I correct?