source: vendor/glibc-tests/glibc/resolv/tst-aton.c

#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>


static struct tests
{
  const char *input;
  int valid;
  uint32_t result;
} tests[] =
{
  { "", 0, 0 },
  { "-1", 0, 0 },
  { "256", 1, 0x00000100 },
  { "256.", 0, 0 },
  { "256a", 0, 0 },
  { "0x100", 1, 0x00000100 },
  { "0200.0x123456", 1, 0x80123456 },
  { "0300.0x89123456.", 0 ,0 },
  { "0100.-0xffff0000", 0, 0 },
  { "0.0xffffff", 1, 0x00ffffff },
  { "0.0x1000000", 0, 0 },
  { "0377.16777215", 1, 0xffffffff },
  { "0377.16777216", 0, 0 },
  { "0x87.077777777", 1, 0x87ffffff },
  { "0x87.0100000000", 0, 0 },
  { "0.1.3", 1, 0x00010003 },
  { "0.256.3", 0, 0 },
  { "256.1.3", 0, 0 },
  { "0.1.0x10000", 0, 0 },
  { "0.1.0xffff", 1, 0x0001ffff },
  { "0.1a.3", 0, 0 },
  { "0.1.a3", 0, 0 },
  { "1.2.3.4", 1, 0x01020304 },
  { "0400.2.3.4", 0, 0 },
  { "1.0x100.3.4", 0, 0 },
  { "1.2.256.4", 0, 0 },
  { "1.2.3.0x100", 0, 0 },
  { "323543357756889", 0, 0 },
  { "10.1.2.3.4", 0, 0},
};


int
main (int argc, char *argv[])
{
  int result = 0;
  size_t cnt;

  for (cnt = 0; cnt < sizeof (tests) / sizeof (tests[0]); ++cnt)
    {
      struct in_addr addr;

      if ((int) inet_aton (tests[cnt].input, &addr) != tests[cnt].valid)
        {
          if (tests[cnt].valid)
            printf ("\"%s\" not seen as valid IP address\n", tests[cnt].input);
          else
            printf ("\"%s\" seen as valid IP address\n", tests[cnt].input);
          result = 1;
        }
      else if (tests[cnt].valid && addr.s_addr != ntohl (tests[cnt].result))
        {
          printf ("\"%s\" not converted correctly: is %08x, should be %08x\n",
                  tests[cnt].input, addr.s_addr, tests[cnt].result);
          result = 1;
        }
    }

  return result;
}