/**----------------------------------------------------------------------------\
| An example of how to create functions with variadic arguments in ANSI C. |
| |
| The preprocessor macro to automatically count arguments is optional; |
| provided only as a convenience. |
\-----------------------------------------------------------------------------*/
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
char *my_variadic(char count, ...){
/* Retrieve variadic arguments. */
va_list strings;
va_start(strings, count);
/* Build concatenated string. */
char *output = "";
int index = 1;
while(count > 0){
/* Get next argument; string to append. */
char *string = va_arg(strings, char*);
/* Get strings' lengths. */
printf("Argument %i: %s\n", index, string);
/* Counters. */
index++;
count--;
}
/* Done. */
va_end(strings);
return output;
}
/* Compiler-dependent preprocessor macro for the automatic counting of arguments.
* Optional; provided only as a convenience. */
#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,_64,_65,_66,_67,_68,_69,_70,_71,_72,_73,_74,_75,_76,_77,_78,_79,_80,_81,_82,_83,_84,_85,_86,_87,_88,_89,_90,_91,_92,_93,_94,_95,_96,_97,_98,_99,_100,_101,_102,_103,_104,_105,_106,_107,_108,_109,_110,_111,_112,_113,_114,_115,_116,_117,_118,_119,_120,_121,_122,_123,_124,_125,_126,_127,N,...) N
#define PP_RSEQ_N() 127,126,125,124,123,122,121,120,119,118,117,116,115,114,113,112,111,110,109,108,107,106,105,104,103,102,101,100,99,98,97,96,95,94,93,92,91,90,89,88,87,86,85,84,83,82,81,80,79,78,77,76,75,74,73,72,71,70,69,68,67,66,65,64,63,62,61,60,59,58,57,56,55,54,53,52,51,50,49,48,47,46,45,44,43,42,41,40,39,38,37,36,35,34,33,32,31,30,29,28,27,26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0
#define my_variadic(...) my_variadic(PP_NARG(__VA_ARGS__), __VA_ARGS__)
/**----------------------------------------------------------------------------\
| Example usage. |
\-----------------------------------------------------------------------------*/
#include <stdio.h>
#include <unistd.h>
int main(int argc, char **argv){
/* Create strings. */
my_variadic("Hello");
printf("--------------------------------------------------------------------------------\n");
my_variadic("Hello", "World");
printf("--------------------------------------------------------------------------------\n");
my_variadic("Hello", "World", "!");
printf("--------------------------------------------------------------------------------\n");
/* Done. */
sleep(3);
return 0;
}