1:
$cppawk '
#include <varg.h>

function f(restargs)
{
  return argcount("f", restargs)
}

BEGIN {
  print f()
  print f(1)
  print f(1, 2)
  print f(1, 2, 3)
  print f(1, 2, 3, 4)
  print f(1, 2, 3, 4, 5)
  print f(1, 2, 3, 4, 5, 6)
  print f(1, 2, 3, 4, 5, 6, 7)
  print f(1, 2, 3, 4, 5, 6, 7, 8)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
  print f(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)
  print f(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)
  print f(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)
  print f(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)
  print f(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)
  print f(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)
  print f(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)
  print f(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)
}'
:
0
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
--
2:
$cppawk '
#include <varg.h>

function f(restargs)
{
  return argcount("f", restargs)
}

BEGIN {
  print f(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)
}
:
ERR
--
3:
$cppawk '
#include <varg.h>
#include <cons.h>

function f(restargs)
{
  return sexp(arglist("f", restargs))
}

BEGIN {
  print f()
  print f(1)
  print f(1, 2)
  print f(1, 2, 3)
  print f(1, 2, 3, 4)
  print f(1, 2, 3, 4, 5)
  print f(1, 2, 3, 4, 5, 6)
  print f(1, 2, 3, 4, 5, 6, 7)
  print f(1, 2, 3, 4, 5, 6, 7, 8)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
  print f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
  print f(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)
  print f(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)
  print f(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)
  print f(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)
  print f(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)
  print f(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)
  print f(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)
  print f(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)
}'
:
nil
(1)
(1 2)
(1 2 3)
(1 2 3 4)
(1 2 3 4 5)
(1 2 3 4 5 6)
(1 2 3 4 5 6 7)
(1 2 3 4 5 6 7 8)
(1 2 3 4 5 6 7 8 9)
(1 2 3 4 5 6 7 8 9 10)
(1 2 3 4 5 6 7 8 9 10 11)
(1 2 3 4 5 6 7 8 9 10 11 12)
(1 2 3 4 5 6 7 8 9 10 11 12 13)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23)
(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24)
(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)
(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)
(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)
(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)
(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)
(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)
(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)
(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)
--
4:
$cppawk '
#include <varg.h>

function f(restargs, i, n)
{
  delete a
  n = argcount("f", restargs)
  argarray("f", a, restargs)
  for (i = 1; i <= n; i++)
    printf "%s,", a[i]
  print
}

BEGIN {
  f()
  f(1)
  f(1, 2)
  f(1, 2, 3)
  f(1, 2, 3, 4)
  f(1, 2, 3, 4, 5)
  f(1, 2, 3, 4, 5, 6)
  f(1, 2, 3, 4, 5, 6, 7)
  f(1, 2, 3, 4, 5, 6, 7, 8)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
  f(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
  f(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)
  f(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)
  f(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)
  f(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)
  f(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)
  f(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)
  f(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)
  f(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)
}'
:

1,
1,2,
1,2,3,
1,2,3,4,
1,2,3,4,5,
1,2,3,4,5,6,
1,2,3,4,5,6,7,
1,2,3,4,5,6,7,8,
1,2,3,4,5,6,7,8,9,
1,2,3,4,5,6,7,8,9,10,
1,2,3,4,5,6,7,8,9,10,11,
1,2,3,4,5,6,7,8,9,10,11,12,
1,2,3,4,5,6,7,8,9,10,11,12,13,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,
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,
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,
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,
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,
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,
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,
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,
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,
--
5:
$cppawk '
#include <varg.h>
#include <cons.h>

function f(restargs)
{
  return list(arg(1), arg(2), arg(3), arg(4),
              arg(5), arg(6), arg(7), arg(8),
              arg(9), arg(10), arg(11), arg(12),
              arg(13), arg(14), arg(15), arg(16),
              arg(17), arg(18), arg(19), arg(20),
              arg(21), arg(22), arg(23), arg(24),
              arg(25), arg(26), arg(27), arg(28),
              arg(29), arg(30), arg(31), arg(32))
}

BEGIN {
  print sexp(f(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))
}'
:
(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)