text: /*
   *******************************************************************************
   * Copyright (C) 1996-2016, International Business Machines
   * Corporation and others. All Rights Reserved.
   *******************************************************************************
  */
  
  #ifndef UDAT_H
  #define UDAT_H
  
  #include "unicode/utypes.h"
  
  #if !UCONFIG_NO_FORMATTING
  
  #include "unicode/localpointer.h"
  #include "unicode/ucal.h"
  #include "unicode/unum.h"
  #include "unicode/udisplaycontext.h"
  #include "unicode/ufieldpositer.h"
  /**
   * \file
   * \brief C API: DateFormat
   *
   * <h2> Date Format C API</h2>
   *
   * Date Format C API  consists of functions that convert dates and
   * times from their internal representations to textual form and back again in a
   * language-independent manner. Converting from the internal representation (milliseconds
   * since midnight, January 1, 1970) to text is known as "formatting," and converting
   * from text to millis is known as "parsing."  We currently define only one concrete
   * structure UDateFormat, which can handle pretty much all normal
   * date formatting and parsing actions.
   * <P>
   * Date Format helps you to format and parse dates for any locale. Your code can
   * be completely independent of the locale conventions for months, days of the
   * week, or even the calendar format: lunar vs. solar.
   * <P>
   * To format a date for the current Locale with default time and date style,
   * use one of the static factory methods:
   * <pre>
   * \code
   *  UErrorCode status = U_ZERO_ERROR;
   *  UChar *myString;
   *  int32_t myStrlen = 0;
   *  UDateFormat* dfmt = udat_open(UDAT_DEFAULT, UDAT_DEFAULT, NULL, NULL, -1, NULL, -1, &status);
   *  myStrlen = udat_format(dfmt, myDate, NULL, myStrlen, NULL, &status);
   *  if (status==U_BUFFER_OVERFLOW_ERROR){
   *      status=U_ZERO_ERROR;
   *      myString=(UChar*)malloc(sizeof(UChar) * (myStrlen+1) );
   *      udat_format(dfmt, myDate, myString, myStrlen+1, NULL, &status);
   *  }
   * \endcode
   * </pre>
   * If you are formatting multiple numbers, it is more efficient to get the
   * format and use it multiple times so that the system doesn't have to fetch the
   * information about the local language and country conventions multiple times.
   * <pre>
   * \code
   *  UErrorCode status = U_ZERO_ERROR;
   *  int32_t i, myStrlen = 0;
   *  UChar* myString;
   *  char buffer[1024];
   *  UDate myDateArr[] = { 0.0, 100000000.0, 2000000000.0 }; // test values
   *  UDateFormat* df = udat_open(UDAT_DEFAULT, UDAT_DEFAULT, NULL, NULL, -1, NULL, 0, &status);
   *  for (i = 0; i < 3; i++) {
   *      myStrlen = udat_format(df, myDateArr[i], NULL, myStrlen, NULL, &status);
   *      if(status == U_BUFFER_OVERFLOW_ERROR){
   *          status = U_ZERO_ERROR;
   *          myString = (UChar*)malloc(sizeof(UChar) * (myStrlen+1) );
   *          udat_format(df, myDateArr[i], myString, myStrlen+1, NULL, &status);
   *          printf("%s\n", u_austrcpy(buffer, myString) );
   *          free(myString);
   *      }
   *  }
   * \endcode
   * </pre>
   * To get specific fields of a date, you can use UFieldPosition to
   * get specific fields.
   * <pre>
   * \code
   *  UErrorCode status = U_ZERO_ERROR;
   *  UFieldPosition pos;
   *  UChar *myString;
   *  int32_t myStrlen = 0;
   *  char buffer[1024];
   *
   *  pos.field = 1;  // Same as the DateFormat::EField enum
   *  UDateFormat* dfmt = udat_open(UDAT_DEFAULT, UDAT_DEFAULT, NULL, -1, NULL, 0, &status);
   *  myStrlen = udat_format(dfmt, myDate, NULL, myStrlen, &pos, &status);
   *  if (status==U_BUFFER_OVERFLOW_ERROR){
   *      status=U_ZERO_ERROR;
   *      myString=(UChar*)malloc(sizeof(UChar) * (myStrlen+1) );
   *      udat_format(dfmt, myDate, myString, myStrlen+1, &pos, &status);
   *  }
   *  printf("date format: %s\n", u_austrcpy(buffer, myString));
   *  buffer[pos.endIndex] = 0;   // NULL terminate the string.
   *  printf("UFieldPosition position equals %s\n", &buffer[pos.beginIndex]);
   * \endcode
   * </pre>
   * To format a date for a different Locale, specify it in the call to
   * udat_open()
   * <pre>
   * \code
   *        UDateFormat* df = udat_open(UDAT_SHORT, UDAT_SHORT, "fr_FR", NULL, -1, NULL, 0, &status);
   * \endcode
   * </pre>
   * You can use a DateFormat API udat_parse() to parse.
   * <pre>
   * \code
   *  UErrorCode status = U_ZERO_ERROR;
   *  int32_t parsepos=0;
   *  UDate myDate = udat_parse(df, myString, u_strlen(myString), &parsepos, &status);
   * \endcode
   * </pre>
   *  You can pass in different options for the arguments for date and time style
   *  to control the length of the result; from SHORT to MEDIUM to LONG to FULL.
   *  The exact result depends on the locale, but generally:
   *  see UDateFormatStyle for more details
   * <ul type=round>
   *   <li>   UDAT_SHORT is completely numeric, such as 12/13/52 or 3:30pm
   *   <li>   UDAT_MEDIUM is longer, such as Jan 12, 1952
   *   <li>   UDAT_LONG is longer, such as January 12, 1952 or 3:30:32pm
   *   <li>   UDAT_FULL is pretty completely specified, such as
   *          Tuesday, April 12, 1952 AD or 3:30:42pm PST.
   * </ul>
   * You can also set the time zone on the format if you wish.
   * <P>
   * You can also use forms of the parse and format methods with Parse Position and
   * UFieldPosition to allow you to
   * <ul type=round>
   *   <li>   Progressively parse through pieces of a string.
   *   <li>   Align any particular field, or find out where it is for selection
   *          on the screen.
   * </ul>
   * <p><strong>Date and Time Patterns:</strong></p>
   *
   * <p>Date and time formats are specified by <em>date and time pattern</em> strings.
   * Within date and time pattern strings, all unquoted ASCII letters [A-Za-z] are reserved
   * as pattern letters representing calendar fields. <code>UDateFormat</code> supports
   * the date and time formatting algorithm and pattern letters defined by
   * <a href="http://www.unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table">UTS#35
   * Unicode Locale Data Markup Language (LDML)</a> and further documented for ICU in the
   * <a href="https://sites.google.com/site/icuprojectuserguide/formatparse/datetime?pli=1#TOC-Date-Field-Symbol-Table">ICU
   * User Guide</a>.</p>
   */
  
  /** A date formatter.
   *  For usage in C programs.
   *  @stable ICU 2.6
   */
  typedef void* UDateFormat;
  
  /** The possible date/time format styles
   *  @stable ICU 2.6
   */
  typedef enum UDateFormatStyle {
      /** Full style */
      UDAT_FULL,
      /** Long style */
      UDAT_LONG,
      /** Medium style */
      UDAT_MEDIUM,
      /** Short style */
      UDAT_SHORT,
      /** Default style */
      UDAT_DEFAULT = UDAT_MEDIUM,
  
      /** Bitfield for relative date */
      UDAT_RELATIVE = (1 << 7),
  
      UDAT_FULL_RELATIVE = UDAT_FULL | UDAT_RELATIVE,
  
      UDAT_LONG_RELATIVE = UDAT_LONG | UDAT_RELATIVE,
  
      UDAT_MEDIUM_RELATIVE = UDAT_MEDIUM | UDAT_RELATIVE,
  
      UDAT_SHORT_RELATIVE = UDAT_SHORT | UDAT_RELATIVE,
  
      /** No style */
      UDAT_NONE = -1,
  
      /**
       * Use the pattern given in the parameter to udat_open
       * @see udat_open
       * @stable ICU 50
       */
      UDAT_PATTERN = -2,
  
  #ifndef U_HIDE_INTERNAL_API
      /** @internal alias to UDAT_PATTERN */
      UDAT_IGNORE = UDAT_PATTERN
  #endif /* U_HIDE_INTERNAL_API */
  } UDateFormatStyle;
  
  /* Skeletons for dates. */
  
  /**
   * Constant for date skeleton with year.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR "y"
  /**
   * Constant for date skeleton with quarter.
   * @stable ICU 51
   */
  #define UDAT_QUARTER "QQQQ"
  /**
   * Constant for date skeleton with abbreviated quarter.
   * @stable ICU 51
   */
  #define UDAT_ABBR_QUARTER "QQQ"
  /**
   * Constant for date skeleton with year and quarter.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_QUARTER "yQQQQ"
  /**
   * Constant for date skeleton with year and abbreviated quarter.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_ABBR_QUARTER "yQQQ"
  /**
   * Constant for date skeleton with month.
   * @stable ICU 4.0
   */
  #define UDAT_MONTH "MMMM"
  /**
   * Constant for date skeleton with abbreviated month.
   * @stable ICU 4.0
   */
  #define UDAT_ABBR_MONTH "MMM"
  /**
   * Constant for date skeleton with numeric month.
   * @stable ICU 4.0
   */
  #define UDAT_NUM_MONTH "M"
  /**
   * Constant for date skeleton with year and month.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_MONTH "yMMMM"
  /**
   * Constant for date skeleton with year and abbreviated month.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_ABBR_MONTH "yMMM"
  /**
   * Constant for date skeleton with year and numeric month.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_NUM_MONTH "yM"
  /**
   * Constant for date skeleton with day.
   * @stable ICU 4.0
   */
  #define UDAT_DAY "d"
  /**
   * Constant for date skeleton with year, month, and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_MONTH_DAY "yMMMMd"
  /**
   * Constant for date skeleton with year, abbreviated month, and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_ABBR_MONTH_DAY "yMMMd"
  /**
   * Constant for date skeleton with year, numeric month, and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_NUM_MONTH_DAY "yMd"
  /**
   * Constant for date skeleton with weekday.
   * @stable ICU 51
   */
  #define UDAT_WEEKDAY "EEEE"
  /**
   * Constant for date skeleton with abbreviated weekday.
   * @stable ICU 51
   */
  #define UDAT_ABBR_WEEKDAY "E"
  /**
   * Constant for date skeleton with year, month, weekday, and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_MONTH_WEEKDAY_DAY "yMMMMEEEEd"
  /**
   * Constant for date skeleton with year, abbreviated month, weekday, and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_ABBR_MONTH_WEEKDAY_DAY "yMMMEd"
  /**
   * Constant for date skeleton with year, numeric month, weekday, and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_YEAR_NUM_MONTH_WEEKDAY_DAY "yMEd"
  /**
   * Constant for date skeleton with long month and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_MONTH_DAY "MMMMd"
  /**
   * Constant for date skeleton with abbreviated month and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_ABBR_MONTH_DAY "MMMd"
  /**
   * Constant for date skeleton with numeric month and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_NUM_MONTH_DAY "Md"
  /**
   * Constant for date skeleton with month, weekday, and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_MONTH_WEEKDAY_DAY "MMMMEEEEd"
  /**
   * Constant for date skeleton with abbreviated month, weekday, and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_ABBR_MONTH_WEEKDAY_DAY "MMMEd"
  /**
   * Constant for date skeleton with numeric month, weekday, and day.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_NUM_MONTH_WEEKDAY_DAY "MEd"
  
  /* Skeletons for times. */
  
  /**
   * Constant for date skeleton with hour, with the locale's preferred hour format (12 or 24).
   * @stable ICU 4.0
   */
  #define UDAT_HOUR "j"
  /**
   * Constant for date skeleton with hour in 24-hour presentation.
   * @stable ICU 51
   */
  #define UDAT_HOUR24 "H"
  /**
   * Constant for date skeleton with minute.
   * @stable ICU 51
   */
  #define UDAT_MINUTE "m"
  /**
   * Constant for date skeleton with hour and minute, with the locale's preferred hour format (12 or 24).
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_HOUR_MINUTE "jm"
  /**
   * Constant for date skeleton with hour and minute in 24-hour presentation.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_HOUR24_MINUTE "Hm"
  /**
   * Constant for date skeleton with second.
   * @stable ICU 51
   */
  #define UDAT_SECOND "s"
  /**
   * Constant for date skeleton with hour, minute, and second,
   * with the locale's preferred hour format (12 or 24).
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_HOUR_MINUTE_SECOND "jms"
  /**
   * Constant for date skeleton with hour, minute, and second in
   * 24-hour presentation.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_HOUR24_MINUTE_SECOND "Hms"
  /**
   * Constant for date skeleton with minute and second.
   * Used in combinations date + time, date + time + zone, or time + zone.
   * @stable ICU 4.0
   */
  #define UDAT_MINUTE_SECOND "ms"
  
  /* Skeletons for time zones. */
  
  /**
   * Constant for <i>generic location format</i>, such as Los Angeles Time;
   * used in combinations date + time + zone, or time + zone.
   * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
   * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
   * @stable ICU 51
   */
  #define UDAT_LOCATION_TZ "VVVV"
  /**
   * Constant for <i>generic non-location format</i>, such as Pacific Time;
   * used in combinations date + time + zone, or time + zone.
   * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
   * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
   * @stable ICU 51
   */
  #define UDAT_GENERIC_TZ "vvvv"
  /**
   * Constant for <i>generic non-location format</i>, abbreviated if possible, such as PT;
   * used in combinations date + time + zone, or time + zone.
   * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
   * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
   * @stable ICU 51
   */
  #define UDAT_ABBR_GENERIC_TZ "v"
  /**
   * Constant for <i>specific non-location format</i>, such as Pacific Daylight Time;
   * used in combinations date + time + zone, or time + zone.
   * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
   * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
   * @stable ICU 51
   */
  #define UDAT_SPECIFIC_TZ "zzzz"
  /**
   * Constant for <i>specific non-location format</i>, abbreviated if possible, such as PDT;
   * used in combinations date + time + zone, or time + zone.
   * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
   * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
   * @stable ICU 51
   */
  #define UDAT_ABBR_SPECIFIC_TZ "z"
  /**
   * Constant for <i>localized GMT/UTC format</i>, such as GMT+8:00 or HPG-8:00;
   * used in combinations date + time + zone, or time + zone.
   * @see <a href="http://unicode.org/reports/tr35/#Date_Format_Patterns">LDML Date Format Patterns</a>
   * @see <a href="http://unicode.org/reports/tr35/#Time_Zone_Fallback">LDML Time Zone Fallback</a>
   * @stable ICU 51
   */
  #define UDAT_ABBR_UTC_TZ "ZZZZ"
  
  /* deprecated skeleton constants */
  
  #ifndef U_HIDE_DEPRECATED_API
  /**
   * Constant for date skeleton with standalone month.
   * @deprecated ICU 50 Use UDAT_MONTH instead.
   */
  #define UDAT_STANDALONE_MONTH "LLLL"
  /**
   * Constant for date skeleton with standalone abbreviated month.
   * @deprecated ICU 50 Use UDAT_ABBR_MONTH instead.
   */
  #define UDAT_ABBR_STANDALONE_MONTH "LLL"
  
  /**
   * Constant for date skeleton with hour, minute, and generic timezone.
   * @deprecated ICU 50 Use instead UDAT_HOUR_MINUTE UDAT_ABBR_GENERIC_TZ or some other timezone presentation.
   */
  #define UDAT_HOUR_MINUTE_GENERIC_TZ "jmv"
  /**
   * Constant for date skeleton with hour, minute, and timezone.
   * @deprecated ICU 50 Use instead UDAT_HOUR_MINUTE UDAT_ABBR_SPECIFIC_TZ or some other timezone presentation.
   */
  #define UDAT_HOUR_MINUTE_TZ "jmz"
  /**
   * Constant for date skeleton with hour and generic timezone.
   * @deprecated ICU 50 Use instead UDAT_HOUR UDAT_ABBR_GENERIC_TZ or some other timezone presentation.
   */
  #define UDAT_HOUR_GENERIC_TZ "jv"
  /**
   * Constant for date skeleton with hour and timezone.
   * @deprecated ICU 50 Use instead UDAT_HOUR UDAT_ABBR_SPECIFIC_TZ or some other timezone presentation.
   */
  #define UDAT_HOUR_TZ "jz"
  #endif /* U_HIDE_DEPRECATED_API */
  
  /**
   * FieldPosition and UFieldPosition selectors for format fields
   * defined by DateFormat and UDateFormat.
   * @stable ICU 3.0
   */
  typedef enum UDateFormatField {
      /**
       * FieldPosition and UFieldPosition selector for 'G' field alignment,
       * corresponding to the UCAL_ERA field.
       * @stable ICU 3.0
       */
      UDAT_ERA_FIELD = 0,
  
      /**
       * FieldPosition and UFieldPosition selector for 'y' field alignment,
       * corresponding to the UCAL_YEAR field.
       * @stable ICU 3.0
       */
      UDAT_YEAR_FIELD = 1,
  
      /**
       * FieldPosition and UFieldPosition selector for 'M' field alignment,
       * corresponding to the UCAL_MONTH field.
       * @stable ICU 3.0
       */
      UDAT_MONTH_FIELD = 2,
  
      /**
       * FieldPosition and UFieldPosition selector for 'd' field alignment,
       * corresponding to the UCAL_DATE field.
       * @stable ICU 3.0
       */
      UDAT_DATE_FIELD = 3,
  
      /**
       * FieldPosition and UFieldPosition selector for 'k' field alignment,
       * corresponding to the UCAL_HOUR_OF_DAY field.
       * UDAT_HOUR_OF_DAY1_FIELD is used for the one-based 24-hour clock.
       * For example, 23:59 + 01:00 results in 24:59.
       * @stable ICU 3.0
       */
      UDAT_HOUR_OF_DAY1_FIELD = 4,
  
      /**
       * FieldPosition and UFieldPosition selector for 'H' field alignment,
       * corresponding to the UCAL_HOUR_OF_DAY field.
       * UDAT_HOUR_OF_DAY0_FIELD is used for the zero-based 24-hour clock.
       * For example, 23:59 + 01:00 results in 00:59.
       * @stable ICU 3.0
       */
      UDAT_HOUR_OF_DAY0_FIELD = 5,
  
      /**
       * FieldPosition and UFieldPosition selector for 'm' field alignment,
       * corresponding to the UCAL_MINUTE field.
       * @stable ICU 3.0
       */
      UDAT_MINUTE_FIELD = 6,
  
      /**
       * FieldPosition and UFieldPosition selector for 's' field alignment,
       * corresponding to the UCAL_SECOND field.
       * @stable ICU 3.0
       */
      UDAT_SECOND_FIELD = 7,
  
      /**
       * FieldPosition and UFieldPosition selector for 'S' field alignment,
       * corresponding to the UCAL_MILLISECOND field.
       *
       * Note: Time formats that use 'S' can display a maximum of three
       * significant digits for fractional seconds, corresponding to millisecond
       * resolution and a fractional seconds sub-pattern of SSS. If the
       * sub-pattern is S or SS, the fractional seconds value will be truncated
       * (not rounded) to the number of display places specified. If the
       * fractional seconds sub-pattern is longer than SSS, the additional
       * display places will be filled with zeros.
       * @stable ICU 3.0
       */
      UDAT_FRACTIONAL_SECOND_FIELD = 8,
  
      /**
       * FieldPosition and UFieldPosition selector for 'E' field alignment,
       * corresponding to the UCAL_DAY_OF_WEEK field.
       * @stable ICU 3.0
       */
      UDAT_DAY_OF_WEEK_FIELD = 9,
  
      /**
       * FieldPosition and UFieldPosition selector for 'D' field alignment,
       * corresponding to the UCAL_DAY_OF_YEAR field.
       * @stable ICU 3.0
       */
      UDAT_DAY_OF_YEAR_FIELD = 10,
  
      /**
       * FieldPosition and UFieldPosition selector for 'F' field alignment,
       * corresponding to the UCAL_DAY_OF_WEEK_IN_MONTH field.
       * @stable ICU 3.0
       */
      UDAT_DAY_OF_WEEK_IN_MONTH_FIELD = 11,
  
      /**
       * FieldPosition and UFieldPosition selector for 'w' field alignment,
       * corresponding to the UCAL_WEEK_OF_YEAR field.
       * @stable ICU 3.0
       */
      UDAT_WEEK_OF_YEAR_FIELD = 12,
  
      /**
       * FieldPosition and UFieldPosition selector for 'W' field alignment,
       * corresponding to the UCAL_WEEK_OF_MONTH field.
       * @stable ICU 3.0
       */
      UDAT_WEEK_OF_MONTH_FIELD = 13,
  
      /**
       * FieldPosition and UFieldPosition selector for 'a' field alignment,
       * corresponding to the UCAL_AM_PM field.
       * @stable ICU 3.0
       */
      UDAT_AM_PM_FIELD = 14,
  
      /**
       * FieldPosition and UFieldPosition selector for 'h' field alignment,
       * corresponding to the UCAL_HOUR field.
       * UDAT_HOUR1_FIELD is used for the one-based 12-hour clock.
       * For example, 11:30 PM + 1 hour results in 12:30 AM.
       * @stable ICU 3.0
       */
      UDAT_HOUR1_FIELD = 15,
  
      /**
       * FieldPosition and UFieldPosition selector for 'K' field alignment,
       * corresponding to the UCAL_HOUR field.
       * UDAT_HOUR0_FIELD is used for the zero-based 12-hour clock.
       * For example, 11:30 PM + 1 hour results in 00:30 AM.
       * @stable ICU 3.0
       */
      UDAT_HOUR0_FIELD = 16,
  
      /**
       * FieldPosition and UFieldPosition selector for 'z' field alignment,
       * corresponding to the UCAL_ZONE_OFFSET and
       * UCAL_DST_OFFSET fields.
       * @stable ICU 3.0
       */
      UDAT_TIMEZONE_FIELD = 17,
  
      /**
       * FieldPosition and UFieldPosition selector for 'Y' field alignment,
       * corresponding to the UCAL_YEAR_WOY field.
       * @stable ICU 3.0
       */
      UDAT_YEAR_WOY_FIELD = 18,
  
      /**
       * FieldPosition and UFieldPosition selector for 'e' field alignment,
       * corresponding to the UCAL_DOW_LOCAL field.
       * @stable ICU 3.0
       */
      UDAT_DOW_LOCAL_FIELD = 19,
  
      /**
       * FieldPosition and UFieldPosition selector for 'u' field alignment,
       * corresponding to the UCAL_EXTENDED_YEAR field.
       * @stable ICU 3.0
       */
      UDAT_EXTENDED_YEAR_FIELD = 20,
  
      /**
       * FieldPosition and UFieldPosition selector for 'g' field alignment,
       * corresponding to the UCAL_JULIAN_DAY field.
       * @stable ICU 3.0
       */
      UDAT_JULIAN_DAY_FIELD = 21,
  
      /**
       * FieldPosition and UFieldPosition selector for 'A' field alignment,
       * corresponding to the UCAL_MILLISECONDS_IN_DAY field.
       * @stable ICU 3.0
       */
      UDAT_MILLISECONDS_IN_DAY_FIELD = 22,
  
      /**
       * FieldPosition and UFieldPosition selector for 'Z' field alignment,
       * corresponding to the UCAL_ZONE_OFFSET and
       * UCAL_DST_OFFSET fields.
       * @stable ICU 3.0
       */
      UDAT_TIMEZONE_RFC_FIELD = 23,
  
      /**
       * FieldPosition and UFieldPosition selector for 'v' field alignment,
       * corresponding to the UCAL_ZONE_OFFSET field.
       * @stable ICU 3.4
       */
      UDAT_TIMEZONE_GENERIC_FIELD = 24,
      /**
       * FieldPosition selector for 'c' field alignment,
       * corresponding to the {@link #UCAL_DOW_LOCAL} field.
       * This displays the stand alone day name, if available.
       * @stable ICU 3.4
       */
      UDAT_STANDALONE_DAY_FIELD = 25,
  
      /**
       * FieldPosition selector for 'L' field alignment,
       * corresponding to the {@link #UCAL_MONTH} field.
       * This displays the stand alone month name, if available.
       * @stable ICU 3.4
       */
      UDAT_STANDALONE_MONTH_FIELD = 26,
  
      /**
       * FieldPosition selector for "Q" field alignment,
       * corresponding to quarters. This is implemented
       * using the {@link #UCAL_MONTH} field. This
       * displays the quarter.
       * @stable ICU 3.6
       */
      UDAT_QUARTER_FIELD = 27,
  
      /**
       * FieldPosition selector for the "q" field alignment,
       * corresponding to stand-alone quarters. This is
       * implemented using the {@link #UCAL_MONTH} field.
       * This displays the stand-alone quarter.
       * @stable ICU 3.6
       */
      UDAT_STANDALONE_QUARTER_FIELD = 28,
  
      /**
       * FieldPosition and UFieldPosition selector for 'V' field alignment,
       * corresponding to the UCAL_ZONE_OFFSET field.
       * @stable ICU 3.8
       */
      UDAT_TIMEZONE_SPECIAL_FIELD = 29,
  
      /**
       * FieldPosition selector for "U" field alignment,
       * corresponding to cyclic year names. This is implemented
       * using the {@link #UCAL_YEAR} field. This displays
       * the cyclic year name, if available.
       * @stable ICU 49
       */
      UDAT_YEAR_NAME_FIELD = 30,
  
      /**
       * FieldPosition selector for 'O' field alignment,
       * corresponding to the UCAL_ZONE_OFFSET and UCAL_DST_OFFSETfields.
       * This displays the localized GMT format.
       * @stable ICU 51
       */
      UDAT_TIMEZONE_LOCALIZED_GMT_OFFSET_FIELD = 31,
  
      /**
       * FieldPosition selector for 'X' field alignment,
       * corresponding to the UCAL_ZONE_OFFSET and UCAL_DST_OFFSETfields.
       * This displays the ISO 8601 local time offset format or UTC indicator ("Z").
       * @stable ICU 51
       */
      UDAT_TIMEZONE_ISO_FIELD = 32,
  
      /**
       * FieldPosition selector for 'x' field alignment,
       * corresponding to the UCAL_ZONE_OFFSET and UCAL_DST_OFFSET fields.
       * This displays the ISO 8601 local time offset format.
       * @stable ICU 51
       */
      UDAT_TIMEZONE_ISO_LOCAL_FIELD = 33,
  
  #ifndef U_HIDE_INTERNAL_API
      /**
       * FieldPosition and UFieldPosition selector for 'r' field alignment,
       * no directly corresponding UCAL_ field.
       * @internal ICU 53
       */
      UDAT_RELATED_YEAR_FIELD = 34,
  #endif /* U_HIDE_INTERNAL_API */
  
  #ifndef U_HIDE_DRAFT_API
      /**
       * FieldPosition selector for 'b' field alignment.
       * Displays midnight and noon for 12am and 12pm, respectively, if available;
       * otherwise fall back to AM / PM.
       * @draft ICU 57
       */
      UDAT_AM_PM_MIDNIGHT_NOON_FIELD = 35,
  
      /* FieldPosition selector for 'B' field alignment.
       * Displays flexible day periods, such as "in the morning", if available.
       * @draft ICU 57
       */
      UDAT_FLEXIBLE_DAY_PERIOD_FIELD = 36,
  #endif /* U_HIDE_DRAFT_API */
  
  #ifndef U_HIDE_INTERNAL_API
      /**
       * FieldPosition and UFieldPosition selector for time separator,
       * no corresponding UCAL_ field. No pattern character is currently
       * defined for this.
       * @internal
       */
      UDAT_TIME_SEPARATOR_FIELD = 37,
  #endif /* U_HIDE_INTERNAL_API */
  
      /**
        * Number of FieldPosition and UFieldPosition selectors for
        * DateFormat and UDateFormat.
        * Valid selectors range from 0 to UDAT_FIELD_COUNT-1.
        * This value is subject to change if new fields are defined
        * in the future.
        * @stable ICU 3.0
        */
      UDAT_FIELD_COUNT = 38
  
  } UDateFormatField;
  
  #ifndef U_HIDE_INTERNAL_API
  /**
   * Is a pattern character defined for UDAT_TIME_SEPARATOR_FIELD?
   * In ICU 55 it was COLON, but that was withdrawn in ICU 56.
   * @internal ICU 56
   */
  #define UDAT_HAS_PATTERN_CHAR_FOR_TIME_SEPARATOR 0
  #endif /* U_HIDE_INTERNAL_API */
  
  /**
   * Maps from a UDateFormatField to the corresponding UCalendarDateFields.
   * Note: since the mapping is many-to-one, there is no inverse mapping.
   * @param field the UDateFormatField.
   * @return the UCalendarDateField.  This will be UCAL_FIELD_COUNT in case
   * of error (e.g., the input field is UDAT_FIELD_COUNT).
   * @stable ICU 4.4
   */
  U_STABLE UCalendarDateFields U_EXPORT2 udat_toCalendarDateField(UDateFormatField field);
  
  /**
   * Open a new UDateFormat for formatting and parsing dates and times.
   * A UDateFormat may be used to format dates in calls to {@link #udat_format },
   * and to parse dates in calls to {@link #udat_parse }.
   * @param timeStyle The style used to format times; one of UDAT_FULL, UDAT_LONG,
   * UDAT_MEDIUM, UDAT_SHORT, UDAT_DEFAULT, or UDAT_NONE (relative time styles
   * are not currently supported).
   * When the pattern parameter is used, pass in UDAT_PATTERN for both timeStyle and dateStyle.
   * @param dateStyle The style used to format dates; one of UDAT_FULL, UDAT_LONG,
   * UDAT_MEDIUM, UDAT_SHORT, UDAT_DEFAULT, UDAT_FULL_RELATIVE, UDAT_LONG_RELATIVE,
   * UDAT_MEDIUM_RELATIVE, UDAT_SHORT_RELATIVE, or UDAT_NONE.
   * When the pattern parameter is used, pass in UDAT_PATTERN for both timeStyle and dateStyle.
   * As currently implemented,
   * relative date formatting only affects a limited range of calendar days before or
   * after the current date, based on the CLDR &lt;field type="day"&gt;/&lt;relative&gt; data: For
   * example, in English, "Yesterday", "Today", and "Tomorrow". Outside of this range,
   * dates are formatted using the corresponding non-relative style.
   * @param locale The locale specifying the formatting conventions
   * @param tzID A timezone ID specifying the timezone to use.  If 0, use
   * the default timezone.
   * @param tzIDLength The length of tzID, or -1 if null-terminated.
   * @param pattern A pattern specifying the format to use.
   * @param patternLength The number of characters in the pattern, or -1 if null-terminated.
   * @param status A pointer to an UErrorCode to receive any errors
   * @return A pointer to a UDateFormat to use for formatting dates and times, or 0 if
   * an error occurred.
   * @stable ICU 2.0
   */
  U_STABLE UDateFormat* U_EXPORT2 udat_open(UDateFormatStyle timeStyle,
                                            UDateFormatStyle dateStyle,
                                            const char* locale,
                                            const UChar* tzID,
                                            int32_t tzIDLength,
                                            const UChar* pattern,
                                            int32_t patternLength,
                                            UErrorCode* status);
  
  /**
  * Close a UDateFormat.
  * Once closed, a UDateFormat may no longer be used.
  * @param format The formatter to close.
  * @stable ICU 2.0
  */
  U_STABLE void U_EXPORT2 udat_close(UDateFormat* format);
  
  /**
   * DateFormat boolean attributes
   *
   * @stable ICU 53
   */
  typedef enum UDateFormatBooleanAttribute {
      /**
        * indicates whether whitespace is allowed. Includes trailing dot tolerance.
        * @stable ICU 53
        */
      UDAT_PARSE_ALLOW_WHITESPACE = 0,
      /**
       * indicates tolerance of numeric data when String data may be assumed. eg: UDAT_YEAR_NAME_FIELD,
       * UDAT_STANDALONE_MONTH_FIELD, UDAT_DAY_OF_WEEK_FIELD
       * @stable ICU 53
       */
      UDAT_PARSE_ALLOW_NUMERIC = 1,
  #ifndef U_HIDE_DRAFT_API
      /**
       * indicates tolerance of a partial literal match
       * e.g. accepting "--mon-02-march-2011" for a pattern of "'--: 'EEE-WW-MMMM-yyyy"
       * @draft ICU 56
       */
      UDAT_PARSE_PARTIAL_LITERAL_MATCH = 2,
      /**
       * indicates tolerance of pattern mismatch between input data and specified format pattern.
       * e.g. accepting "September" for a month pattern of MMM ("Sep")
       * @draft ICU 56
       */
      UDAT_PARSE_MULTIPLE_PATTERNS_FOR_MATCH = 3,
  #endif /* U_HIDE_DRAFT_API */
      /**
       * count boolean date format constants
       * @stable ICU 53
       */
      UDAT_BOOLEAN_ATTRIBUTE_COUNT = 4
  } UDateFormatBooleanAttribute;
  
  /**
   * Get a boolean attribute associated with a UDateFormat.
   * An example would be a true value for a key of UDAT_PARSE_ALLOW_WHITESPACE indicating allowing whitespace leniency.
   * If the formatter does not understand the attribute, -1 is returned.
   * @param fmt The formatter to query.
   * @param attr The attribute to query; e.g. UDAT_PARSE_ALLOW_WHITESPACE.
   * @param status A pointer to an UErrorCode to receive any errors
   * @return The value of attr.
   * @stable ICU 53
   */
  U_STABLE UBool U_EXPORT2 udat_getBooleanAttribute(const UDateFormat* fmt, UDateFormatBooleanAttribute attr, UErrorCode* status);
  
  /**
   * Set a boolean attribute associated with a UDateFormat.
   * An example of a boolean attribute is parse leniency control.  If the formatter does not understand
   * the attribute, the call is ignored.
   * @param fmt The formatter to set.
   * @param attr The attribute to set; one of UDAT_PARSE_ALLOW_WHITESPACE or UDAT_PARSE_ALLOW_NUMERIC
   * @param newValue The new value of attr.
   * @param status A pointer to an UErrorCode to receive any errors
   * @stable ICU 53
   */
  U_STABLE void U_EXPORT2 udat_setBooleanAttribute(UDateFormat* fmt, UDateFormatBooleanAttribute attr, UBool newValue, UErrorCode* status);
  
  #if U_SHOW_CPLUSPLUS_API
  
  U_NAMESPACE_BEGIN
  
  /**
   * \class LocalUDateFormatPointer
   * "Smart pointer" class, closes a UDateFormat via udat_close().
   * For most methods see the LocalPointerBase base class.
   *
   * @see LocalPointerBase
   * @see LocalPointer
   * @stable ICU 4.4
   */
  U_DEFINE_LOCAL_OPEN_POINTER(LocalUDateFormatPointer, UDateFormat, udat_close);
  
  U_NAMESPACE_END
  
  #endif
  
  /**
   * Open a copy of a UDateFormat.
   * This function performs a deep copy.
   * @param fmt The format to copy
   * @param status A pointer to an UErrorCode to receive any errors.
   * @return A pointer to a UDateFormat identical to fmt.
   * @stable ICU 2.0
   */
  U_STABLE UDateFormat* U_EXPORT2 udat_clone(const UDateFormat* fmt, UErrorCode* status);
  
  /**
  * Format a date using a UDateFormat.
  * The date will be formatted using the conventions specified in {@link #udat_open }
  * @param format The formatter to use
  * @param dateToFormat The date to format
  * @param result A pointer to a buffer to receive the formatted number.
  * @param resultLength The maximum size of result.
  * @param position A pointer to a UFieldPosition.  On input, position->field
  * is read.  On output, position->beginIndex and position->endIndex indicate
  * the beginning and ending indices of field number position->field, if such
  * a field exists.  This parameter may be NULL, in which case no field
  * position data is returned.
  * @param status A pointer to an UErrorCode to receive any errors
  * @return The total buffer size needed; if greater than resultLength, the output was truncated.
  * @see udat_parse
  * @see UFieldPosition
  * @stable ICU 2.0
  */
  U_STABLE int32_t U_EXPORT2 udat_format(
      const UDateFormat* format, UDate dateToFormat, UChar* result, int32_t resultLength, UFieldPosition* position, UErrorCode* status);
  
  /**
  * Format a date using an UDateFormat.
  * The date will be formatted using the conventions specified in {@link #udat_open }
  * @param format The formatter to use
  * @param calendar The calendar to format. The calendar instance might be
  *                 mutated if fields are not yet fully calculated, though
  *                 the function won't change the logical date and time held
  *                 by the instance.
  * @param result A pointer to a buffer to receive the formatted number.
  * @param capacity The maximum size of result.
  * @param position A pointer to a UFieldPosition.  On input, position->field
  * is read.  On output, position->beginIndex and position->endIndex indicate
  * the beginning and ending indices of field number position->field, if such
  * a field exists.  This parameter may be NULL, in which case no field
  * position data is returned.
  * @param status A pointer to an UErrorCode to receive any errors
  * @return The total buffer size needed; if greater than resultLength, the output was truncated.
  * @see udat_format
  * @see udat_parseCalendar
  * @see UFieldPosition
  * @stable ICU 55
  */
  U_STABLE int32_t U_EXPORT2 udat_formatCalendar(
      const UDateFormat* format, UCalendar* calendar, UChar* result, int32_t capacity, UFieldPosition* position, UErrorCode* status);
  
  /**
  * Format a date using a UDateFormat.
  * The date will be formatted using the conventions specified in {@link #udat_open}
  * @param format
  *          The formatter to use
  * @param dateToFormat
  *          The date to format
  * @param result
  *          A pointer to a buffer to receive the formatted number.
  * @param resultLength
  *          The maximum size of result.
  * @param fpositer
  *          A pointer to a UFieldPositionIterator created by {@link #ufieldpositer_open}
  *          (may be NULL if field position information is not needed). Any
  *          iteration information already present in the UFieldPositionIterator
  *          will be deleted, and the iterator will be reset to apply to the
  *          fields in the formatted string created by this function call; the
  *          field values provided by {@link #ufieldpositer_next} will be from the
  *          UDateFormatField enum.
  * @param status
  *          A pointer to a UErrorCode to receive any errors
  * @return
  *          The total buffer size needed; if greater than resultLength, the output was truncated.
  * @see udat_parse
  * @see UFieldPositionIterator
  * @stable ICU 55
  */
  U_STABLE int32_t U_EXPORT2 udat_formatForFields(const UDateFormat* format,
                                                  UDate dateToFormat,
                                                  UChar* result,
                                                  int32_t resultLength,
                                                  UFieldPositionIterator* fpositer,
                                                  UErrorCode* status);
  
  /**
  * Format a date using a UDateFormat.
  * The date will be formatted using the conventions specified in {@link #udat_open }
  * @param format
  *          The formatter to use
  * @param calendar
  *          The calendar to format. The calendar instance might be mutated if fields
  *          are not yet fully calculated, though the function won't change the logical
  *          date and time held by the instance.
  * @param result
  *          A pointer to a buffer to receive the formatted number.
  * @param capacity
  *          The maximum size of result.
  * @param fpositer
  *          A pointer to a UFieldPositionIterator created by {@link #ufieldpositer_open}
  *          (may be NULL if field position information is not needed). Any
  *          iteration information already present in the UFieldPositionIterator
  *          will be deleted, and the iterator will be reset to apply to the
  *          fields in the formatted string created by this function call; the
  *          field values provided by {@link #ufieldpositer_next} will be from the
  *          UDateFormatField enum.
  * @param status
  *          A pointer to a UErrorCode to receive any errors
  * @return
  *          The total buffer size needed; if greater than resultLength, the output was truncated.
  * @see udat_format
  * @see udat_parseCalendar
  * @see UFieldPositionIterator
  * @stable ICU 55
  */
  U_STABLE int32_t U_EXPORT2 udat_formatCalendarForFields(
      const UDateFormat* format, UCalendar* calendar, UChar* result, int32_t capacity, UFieldPositionIterator* fpositer, UErrorCode* status);
  
  /**
  * Parse a string into an date/time using a UDateFormat.
  * The date will be parsed using the conventions specified in {@link #udat_open }.
  * <P>
  * Note that the normal date formats associated with some calendars - such
  * as the Chinese lunar calendar - do not specify enough fields to enable
  * dates to be parsed unambiguously. In the case of the Chinese lunar
  * calendar, while the year within the current 60-year cycle is specified,
  * the number of such cycles since the start date of the calendar (in the
  * UCAL_ERA field of the UCalendar object) is not normally part of the format,
  * and parsing may assume the wrong era. For cases such as this it is
  * recommended that clients parse using udat_parseCalendar with the UCalendar
  * passed in set to the current date, or to a date within the era/cycle that
  * should be assumed if absent in the format.
  *
  * @param format The formatter to use.
  * @param text The text to parse.
  * @param textLength The length of text, or -1 if null-terminated.
  * @param parsePos If not 0, on input a pointer to an integer specifying the offset at which
  * to begin parsing.  If not 0, on output the offset at which parsing ended.
  * @param status A pointer to an UErrorCode to receive any errors
  * @return The value of the parsed date/time
  * @see udat_format
  * @stable ICU 2.0
  */
  U_STABLE UDate U_EXPORT2
  udat_parse(const UDateFormat* format, const UChar* text, int32_t textLength, int32_t* parsePos, UErrorCode* status);
  
  /**
  * Parse a string into an date/time using a UDateFormat.
  * The date will be parsed using the conventions specified in {@link #udat_open }.
  * @param format The formatter to use.
  * @param calendar A calendar set on input to the date and time to be used for
  *                 missing values in the date/time string being parsed, and set
  *                 on output to the parsed date/time. When the calendar type is
  *                 different from the internal calendar held by the UDateFormat
  *                 instance, the internal calendar will be cloned to a work
  *                 calendar set to the same milliseconds and time zone as this
  *                 calendar parameter, field values will be parsed based on the
  *                 work calendar, then the result (milliseconds and time zone)
  *                 will be set in this calendar.
  * @param text The text to parse.
  * @param textLength The length of text, or -1 if null-terminated.
  * @param parsePos If not 0, on input a pointer to an integer specifying the offset at which
  * to begin parsing.  If not 0, on output the offset at which parsing ended.
  * @param status A pointer to an UErrorCode to receive any errors
  * @see udat_format
  * @stable ICU 2.0
  */
  U_STABLE void U_EXPORT2 udat_parseCalendar(
      const UDateFormat* format, UCalendar* calendar, const UChar* text, int32_t textLength, int32_t* parsePos, UErrorCode* status);
  
  /**
  * Determine if an UDateFormat will perform lenient parsing.
  * With lenient parsing, the parser may use heuristics to interpret inputs that do not
  * precisely match the pattern. With strict parsing, inputs must match the pattern.
  * @param fmt The formatter to query
  * @return TRUE if fmt is set to perform lenient parsing, FALSE otherwise.
  * @see udat_setLenient
  * @stable ICU 2.0
  */
  U_STABLE UBool U_EXPORT2 udat_isLenient(const UDateFormat* fmt);
  
  /**
  * Specify whether an UDateFormat will perform lenient parsing.
  * With lenient parsing, the parser may use heuristics to interpret inputs that do not
  * precisely match the pattern. With strict parsing, inputs must match the pattern.
  * @param fmt The formatter to set
  * @param isLenient TRUE if fmt should perform lenient parsing, FALSE otherwise.
  * @see dat_isLenient
  * @stable ICU 2.0
  */
  U_STABLE void U_EXPORT2 udat_setLenient(UDateFormat* fmt, UBool isLenient);
  
  /**
  * Get the UCalendar associated with an UDateFormat.
  * A UDateFormat uses a UCalendar to convert a raw value to, for example,
  * the day of the week.
  * @param fmt The formatter to query.
  * @return A pointer to the UCalendar used by fmt.
  * @see udat_setCalendar
  * @stable ICU 2.0
  */
  U_STABLE const UCalendar* U_EXPORT2 udat_getCalendar(const UDateFormat* fmt);
  
  /**
  * Set the UCalendar associated with an UDateFormat.
  * A UDateFormat uses a UCalendar to convert a raw value to, for example,
  * the day of the week.
  * @param fmt The formatter to set.
  * @param calendarToSet A pointer to an UCalendar to be used by fmt.
  * @see udat_setCalendar
  * @stable ICU 2.0
  */
  U_STABLE void U_EXPORT2 udat_setCalendar(UDateFormat* fmt, const UCalendar* calendarToSet);
  
  /**
  * Get the UNumberFormat associated with an UDateFormat.
  * A UDateFormat uses a UNumberFormat to format numbers within a date,
  * for example the day number.
  * @param fmt The formatter to query.
  * @return A pointer to the UNumberFormat used by fmt to format numbers.
  * @see udat_setNumberFormat
  * @stable ICU 2.0
  */
  U_STABLE const UNumberFormat* U_EXPORT2 udat_getNumberFormat(const UDateFormat* fmt);
  
  /**
  * Get the UNumberFormat for specific field associated with an UDateFormat.
  * For example: 'y' for year and 'M' for month
  * @param fmt The formatter to query.
  * @param field the field to query
  * @return A pointer to the UNumberFormat used by fmt to format field numbers.
  * @see udat_setNumberFormatForField
  * @stable ICU 54
  */
  U_STABLE const UNumberFormat* U_EXPORT2 udat_getNumberFormatForField(const UDateFormat* fmt, UChar field);
  
  /**
  * Set the UNumberFormat for specific field associated with an UDateFormat.
  * It can be a single field like: "y"(year) or "M"(month)
  * It can be several field combined together: "yM"(year and month)
  * Note:
  * 1 symbol field is enough for multiple symbol field (so "y" will override "yy", "yyy")
  * If the field is not numeric, then override has no effect (like "MMM" will use abbreviation, not numerical field)
  *
  * @param fields the fields to set
  * @param fmt The formatter to set.
  * @param numberFormatToSet A pointer to the UNumberFormat to be used by fmt to format numbers.
  * @param status error code passed around (memory allocation or invalid fields)
  * @see udat_getNumberFormatForField
  * @stable ICU 54
  */
  U_STABLE void U_EXPORT2 udat_adoptNumberFormatForFields(UDateFormat* fmt,
                                                          const UChar* fields,
                                                          UNumberFormat* numberFormatToSet,
                                                          UErrorCode* status);
  /**
  * Set the UNumberFormat associated with an UDateFormat.
  * A UDateFormat uses a UNumberFormat to format numbers within a date,
  * for example the day number.
  * This method also clears per field NumberFormat instances previously
  * set by {@see udat_setNumberFormatForField}
  * @param fmt The formatter to set.
  * @param numberFormatToSet A pointer to the UNumberFormat to be used by fmt to format numbers.
  * @see udat_getNumberFormat
  * @see udat_setNumberFormatForField
  * @stable ICU 2.0
  */
  U_STABLE void U_EXPORT2 udat_setNumberFormat(UDateFormat* fmt, const UNumberFormat* numberFormatToSet);
  /**
  * Adopt the UNumberFormat associated with an UDateFormat.
  * A UDateFormat uses a UNumberFormat to format numbers within a date,
  * for example the day number.
  * @param fmt The formatter to set.
  * @param numberFormatToAdopt A pointer to the UNumberFormat to be used by fmt to format numbers.
  * @see udat_getNumberFormat
  * @stable ICU 54
  */
  U_STABLE void U_EXPORT2 udat_adoptNumberFormat(UDateFormat* fmt, UNumberFormat* numberFormatToAdopt);
  /**
  * Get a locale for which date/time formatting patterns are available.
  * A UDateFormat in a locale returned by this function will perform the correct
  * formatting and parsing for the locale.
  * @param localeIndex The index of the desired locale.
  * @return A locale for which date/time formatting patterns are available, or 0 if none.
  * @see udat_countAvailable
  * @stable ICU 2.0
  */
  U_STABLE const char* U_EXPORT2 udat_getAvailable(int32_t localeIndex);
  
  /**
  * Determine how many locales have date/time  formatting patterns available.
  * This function is most useful as determining the loop ending condition for
  * calls to {@link #udat_getAvailable }.
  * @return The number of locales for which date/time formatting patterns are available.
  * @see udat_getAvailable
  * @stable ICU 2.0
  */
  U_STABLE int32_t U_EXPORT2 udat_countAvailable(void);
  
  /**
  * Get the year relative to which all 2-digit years are interpreted.
  * For example, if the 2-digit start year is 2100, the year 99 will be
  * interpreted as 2199.
  * @param fmt The formatter to query.
  * @param status A pointer to an UErrorCode to receive any errors
  * @return The year relative to which all 2-digit years are interpreted.
  * @see udat_Set2DigitYearStart
  * @stable ICU 2.0
  */
  U_STABLE UDate U_EXPORT2 udat_get2DigitYearStart(const UDateFormat* fmt, UErrorCode* status);
  
  /**
  * Set the year relative to which all 2-digit years will be interpreted.
  * For example, if the 2-digit start year is 2100, the year 99 will be
  * interpreted as 2199.
  * @param fmt The formatter to set.
  * @param d The year relative to which all 2-digit years will be interpreted.
  * @param status A pointer to an UErrorCode to receive any errors
  * @see udat_Set2DigitYearStart
  * @stable ICU 2.0
  */
  U_STABLE void U_EXPORT2 udat_set2DigitYearStart(UDateFormat* fmt, UDate d, UErrorCode* status);
  
  /**
  * Extract the pattern from a UDateFormat.
  * The pattern will follow the pattern syntax rules.
  * @param fmt The formatter to query.
  * @param localized TRUE if the pattern should be localized, FALSE otherwise.
  * @param result A pointer to a buffer to receive the pattern.
  * @param resultLength The maximum size of result.
  * @param status A pointer to an UErrorCode to receive any errors
  * @return The total buffer size needed; if greater than resultLength, the output was truncated.
  * @see udat_applyPattern
  * @stable ICU 2.0
  */
  U_STABLE int32_t U_EXPORT2 udat_toPattern(const UDateFormat* fmt, UBool localized, UChar* result, int32_t resultLength, UErrorCode* status);
  
  /**
  * Set the pattern used by an UDateFormat.
  * The pattern should follow the pattern syntax rules.
  * @param format The formatter to set.
  * @param localized TRUE if the pattern is localized, FALSE otherwise.
  * @param pattern The new pattern
  * @param patternLength The length of pattern, or -1 if null-terminated.
  * @see udat_toPattern
  * @stable ICU 2.0
  */
  U_STABLE void U_EXPORT2 udat_applyPattern(UDateFormat* format, UBool localized, const UChar* pattern, int32_t patternLength);
  
  /**
   * The possible types of date format symbols
   * @stable ICU 2.6
   */
  typedef enum UDateFormatSymbolType {
      /** The era names, for example AD */
      UDAT_ERAS,
      /** The month names, for example February */
      UDAT_MONTHS,
      /** The short month names, for example Feb. */
      UDAT_SHORT_MONTHS,
      /** The CLDR-style format "wide" weekday names, for example Monday */
      UDAT_WEEKDAYS,
      /**
       * The CLDR-style format "abbreviated" (not "short") weekday names, for example "Mon."
       * For the CLDR-style format "short" weekday names, use UDAT_SHORTER_WEEKDAYS.
       */
      UDAT_SHORT_WEEKDAYS,
      /** The AM/PM names, for example AM */
      UDAT_AM_PMS,
      /** The localized characters */
      UDAT_LOCALIZED_CHARS,
      /** The long era names, for example Anno Domini */
      UDAT_ERA_NAMES,
      /** The narrow month names, for example F */
      UDAT_NARROW_MONTHS,
      /** The CLDR-style format "narrow" weekday names, for example "M" */
      UDAT_NARROW_WEEKDAYS,
      /** Standalone context versions of months */
      UDAT_STANDALONE_MONTHS,
      UDAT_STANDALONE_SHORT_MONTHS,
      UDAT_STANDALONE_NARROW_MONTHS,
      /** The CLDR-style stand-alone "wide" weekday names */
      UDAT_STANDALONE_WEEKDAYS,
      /**
       * The CLDR-style stand-alone "abbreviated" (not "short") weekday names.
       * For the CLDR-style stand-alone "short" weekday names, use UDAT_STANDALONE_SHORTER_WEEKDAYS.
       */
      UDAT_STANDALONE_SHORT_WEEKDAYS,
      /** The CLDR-style stand-alone "narrow" weekday names */
      UDAT_STANDALONE_NARROW_WEEKDAYS,
      /** The quarters, for example 1st Quarter */
      UDAT_QUARTERS,
      /** The short quarter names, for example Q1 */
      UDAT_SHORT_QUARTERS,
      /** Standalone context versions of quarters */
      UDAT_STANDALONE_QUARTERS,
      UDAT_STANDALONE_SHORT_QUARTERS,
      /**
       * The CLDR-style short weekday names, e.g. "Su", Mo", etc.
       * These are named "SHORTER" to contrast with the constants using _SHORT_
       * above, which actually get the CLDR-style *abbreviated* versions of the
       * corresponding names.
       * @stable ICU 51
       */
      UDAT_SHORTER_WEEKDAYS,
      /**
       * Standalone version of UDAT_SHORTER_WEEKDAYS.
       * @stable ICU 51
       */
      UDAT_STANDALONE_SHORTER_WEEKDAYS,
      /**
       * Cyclic year names (only supported for some calendars, and only for FORMAT usage;
       * udat_setSymbols not supported for UDAT_CYCLIC_YEARS_WIDE)
       * @stable ICU 54
       */
      UDAT_CYCLIC_YEARS_WIDE,
      /**
       * Cyclic year names (only supported for some calendars, and only for FORMAT usage)
       * @stable ICU 54
       */
      UDAT_CYCLIC_YEARS_ABBREVIATED,
      /**
       * Cyclic year names (only supported for some calendars, and only for FORMAT usage;
       * udat_setSymbols not supported for UDAT_CYCLIC_YEARS_NARROW)
       * @stable ICU 54
       */
      UDAT_CYCLIC_YEARS_NARROW,
      /**
       * Calendar zodiac  names (only supported for some calendars, and only for FORMAT usage;
       * udat_setSymbols not supported for UDAT_ZODIAC_NAMES_WIDE)
       * @stable ICU 54
       */
      UDAT_ZODIAC_NAMES_WIDE,
      /**
       * Calendar zodiac  names (only supported for some calendars, and only for FORMAT usage)
       * @stable ICU 54
       */
      UDAT_ZODIAC_NAMES_ABBREVIATED,
      /**
       * Calendar zodiac  names (only supported for some calendars, and only for FORMAT usage;
       * udat_setSymbols not supported for UDAT_ZODIAC_NAMES_NARROW)
       * @stable ICU 54
       */
      UDAT_ZODIAC_NAMES_NARROW
  } UDateFormatSymbolType;
  
  struct UDateFormatSymbols;
  /** Date format symbols.
   *  For usage in C programs.
   *  @stable ICU 2.6
   */
  typedef struct UDateFormatSymbols UDateFormatSymbols;
  
  /**
  * Get the symbols associated with an UDateFormat.
  * The symbols are what a UDateFormat uses to represent locale-specific data,
  * for example month or day names.
  * @param fmt The formatter to query.
  * @param type The type of symbols to get.  One of UDAT_ERAS, UDAT_MONTHS, UDAT_SHORT_MONTHS,
  * UDAT_WEEKDAYS, UDAT_SHORT_WEEKDAYS, UDAT_AM_PMS, or UDAT_LOCALIZED_CHARS
  * @param symbolIndex The desired symbol of type type.
  * @param result A pointer to a buffer to receive the pattern.
  * @param resultLength The maximum size of result.
  * @param status A pointer to an UErrorCode to receive any errors
  * @return The total buffer size needed; if greater than resultLength, the output was truncated.
  * @see udat_countSymbols
  * @see udat_setSymbols
  * @stable ICU 2.0
  */
  U_STABLE int32_t U_EXPORT2 udat_getSymbols(
      const UDateFormat* fmt, UDateFormatSymbolType type, int32_t symbolIndex, UChar* result, int32_t resultLength, UErrorCode* status);
  
  /**
  * Count the number of particular symbols for an UDateFormat.
  * This function is most useful as for detemining the loop termination condition
  * for calls to {@link #udat_getSymbols }.
  * @param fmt The formatter to query.
  * @param type The type of symbols to count.  One of UDAT_ERAS, UDAT_MONTHS, UDAT_SHORT_MONTHS,
  * UDAT_WEEKDAYS, UDAT_SHORT_WEEKDAYS, UDAT_AM_PMS, or UDAT_LOCALIZED_CHARS
  * @return The number of symbols of type type.
  * @see udat_getSymbols
  * @see udat_setSymbols
  * @stable ICU 2.0
  */
  U_STABLE int32_t U_EXPORT2 udat_countSymbols(const UDateFormat* fmt, UDateFormatSymbolType type);
  
  /**
  * Set the symbols associated with an UDateFormat.
  * The symbols are what a UDateFormat uses to represent locale-specific data,
  * for example month or day names.
  * @param format The formatter to set
  * @param type The type of symbols to set.  One of UDAT_ERAS, UDAT_MONTHS, UDAT_SHORT_MONTHS,
  * UDAT_WEEKDAYS, UDAT_SHORT_WEEKDAYS, UDAT_AM_PMS, or UDAT_LOCALIZED_CHARS
  * @param symbolIndex The index of the symbol to set of type type.
  * @param value The new value
  * @param valueLength The length of value, or -1 if null-terminated
  * @param status A pointer to an UErrorCode to receive any errors
  * @see udat_getSymbols
  * @see udat_countSymbols
  * @stable ICU 2.0
  */
  U_STABLE void U_EXPORT2 udat_setSymbols(
      UDateFormat* format, UDateFormatSymbolType type, int32_t symbolIndex, UChar* value, int32_t valueLength, UErrorCode* status);
  
  /**
   * Get the locale for this date format object.
   * You can choose between valid and actual locale.
   * @param fmt The formatter to get the locale from
   * @param type type of the locale we're looking for (valid or actual)
   * @param status error code for the operation
   * @return the locale name
   * @stable ICU 2.8
   */
  U_STABLE const char* U_EXPORT2 udat_getLocaleByType(const UDateFormat* fmt, ULocDataLocaleType type, UErrorCode* status);
  
  /**
   * Set a particular UDisplayContext value in the formatter, such as
   * UDISPCTX_CAPITALIZATION_FOR_STANDALONE.
   * @param fmt The formatter for which to set a UDisplayContext value.
   * @param value The UDisplayContext value to set.
   * @param status A pointer to an UErrorCode to receive any errors
   * @stable ICU 51
   */
  U_DRAFT void U_EXPORT2 udat_setContext(UDateFormat* fmt, UDisplayContext value, UErrorCode* status);
  
  /**
   * Get the formatter's UDisplayContext value for the specified UDisplayContextType,
   * such as UDISPCTX_TYPE_CAPITALIZATION.
   * @param fmt The formatter to query.
   * @param type The UDisplayContextType whose value to return
   * @param status A pointer to an UErrorCode to receive any errors
   * @return The UDisplayContextValue for the specified type.
   * @stable ICU 53
   */
  U_STABLE UDisplayContext U_EXPORT2 udat_getContext(const UDateFormat* fmt, UDisplayContextType type, UErrorCode* status);
  
  #ifndef U_HIDE_INTERNAL_API
  /**
  * Extract the date pattern from a UDateFormat set for relative date formatting.
  * The pattern will follow the pattern syntax rules.
  * @param fmt The formatter to query.
  * @param result A pointer to a buffer to receive the pattern.
  * @param resultLength The maximum size of result.
  * @param status A pointer to a UErrorCode to receive any errors
  * @return The total buffer size needed; if greater than resultLength, the output was truncated.
  * @see udat_applyPatternRelative
  * @internal ICU 4.2 technology preview
  */
  U_INTERNAL int32_t U_EXPORT2 udat_toPatternRelativeDate(const UDateFormat* fmt, UChar* result, int32_t resultLength, UErrorCode* status);
  
  /**
  * Extract the time pattern from a UDateFormat set for relative date formatting.
  * The pattern will follow the pattern syntax rules.
  * @param fmt The formatter to query.
  * @param result A pointer to a buffer to receive the pattern.
  * @param resultLength The maximum size of result.
  * @param status A pointer to a UErrorCode to receive any errors
  * @return The total buffer size needed; if greater than resultLength, the output was truncated.
  * @see udat_applyPatternRelative
  * @internal ICU 4.2 technology preview
  */
  U_INTERNAL int32_t U_EXPORT2 udat_toPatternRelativeTime(const UDateFormat* fmt, UChar* result, int32_t resultLength, UErrorCode* status);
  
  /**
  * Set the date & time patterns used by a UDateFormat set for relative date formatting.
  * The patterns should follow the pattern syntax rules.
  * @param format The formatter to set.
  * @param datePattern The new date pattern
  * @param datePatternLength The length of datePattern, or -1 if null-terminated.
  * @param timePattern The new time pattern
  * @param timePatternLength The length of timePattern, or -1 if null-terminated.
  * @param status A pointer to a UErrorCode to receive any errors
  * @see udat_toPatternRelativeDate, udat_toPatternRelativeTime
  * @internal ICU 4.2 technology preview
  */
  U_INTERNAL void U_EXPORT2 udat_applyPatternRelative(UDateFormat* format,
                                                      const UChar* datePattern,
                                                      int32_t datePatternLength,
                                                      const UChar* timePattern,
                                                      int32_t timePatternLength,
                                                      UErrorCode* status);
  
  /**
   * @internal
   * @see udat_open
   */
  typedef UDateFormat*(U_EXPORT2* UDateFormatOpener)(UDateFormatStyle timeStyle,
                                                     UDateFormatStyle dateStyle,
                                                     const char* locale,
                                                     const UChar* tzID,
                                                     int32_t tzIDLength,
                                                     const UChar* pattern,
                                                     int32_t patternLength,
                                                     UErrorCode* status);
  
  /**
   * Register a provider factory
   * @internal ICU 49
   */
  U_INTERNAL void U_EXPORT2 udat_registerOpener(UDateFormatOpener opener, UErrorCode* status);
  
  /**
   * Un-Register a provider factory
   * @internal ICU 49
   */
  U_INTERNAL UDateFormatOpener U_EXPORT2 udat_unregisterOpener(UDateFormatOpener opener, UErrorCode* status);
  #endif /* U_HIDE_INTERNAL_API */
  
  #endif /* #if !UCONFIG_NO_FORMATTING */
  
  #endif
  