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  1. #define _GNU_SOURCE
  2. #include <stdio.h>
  3. #include <time.h>
  4. #include <string.h>
  5.  
  6. static int
  7. is_valid_iso8601_date_value(char *in)
  8. {
  9.     struct tm result;
  10.     char **f;
  11.     char *ret;
  12.     char *formats[] = {
  13.         "%Y",
  14.         "%Y-%m",
  15.         "%y-%m",
  16.         "%Y-%m-%d",
  17.         "%y-%m-%d",
  18.         "%Y%m%d",
  19.         "%y%m%d",
  20.         "%Y-%m-%d %T",
  21.         "%y-%m-%d %T",
  22.         "%Y%m%d%H%M%S",
  23.         "%y%m%d%H%M%S",
  24.         "%Y-%m-%dT%T",
  25.         "%y-%m-%dT%T",
  26.         "%Y-%m-%dT%TZ",
  27.         "%y-%m-%dT%TZ",
  28.         "%Y-%m-%d %TZ",
  29.         "%y-%m-%d %TZ",
  30.         "%Y%m%dT%TZ",
  31.         "%y%m%dT%TZ",
  32.         "%Y%m%d %TZ",
  33.         "%y%m%d %TZ",
  34.         NULL
  35.     };
  36.  
  37.     memset(&result, 0, sizeof(result));
  38.  
  39.     for (f = formats; f && *f; f++)
  40.     {
  41.         ret = strptime(in, *f, &result);
  42.         if (ret && *ret == '\0')
  43.             return 1;
  44.     }
  45.  
  46.     return 0;
  47. }
  48.  
  49. int main(void) {
  50.  
  51. 	char date_str[] = "2010-01-01T01:01:01Z";
  52.  
  53.     if (is_valid_iso8601_date_value(date_str))
  54.     {
  55.     	printf("%s is a valid iso8601 date!", date_str);
  56.         return 0;
  57.     }
  58.     else
  59.     {
  60.     	printf("%s is not a valid iso8601 date!", date_str);
  61. 		return 1;
  62.     }
  63. }
  64.  
Success #stdin #stdout 0s 2248KB
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2010-01-01T01:01:01Z is a valid iso8601 date!
https://ideone.com/4Em3v1
language:
C (gcc 8.3)
created:
10 years ago
visibility:
public

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