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====== DosSetDateTime ======

This call is used to set the date and time that are maintained by the operating system.

===== Syntax =====

<code c>
DosSetDateTime (DateTime)
</code>

===== Parameters =====

  * DateTime ([[PDATETIME]]) - input : Address of the date and time structure:
    * hours ([[UCHAR]]) - Current hour (0-23)
    * minutes ([[UCHAR]]) - Current minute (0-59)
    * seconds ([[UCHAR]]) - Current second (0-59)
    * hundredths ([[UCHAR]]) - Current hundredth of a second (0-99)
    * day ([[UCHAR]]) - Current day (1-31)
    * month ([[UCHAR]]) - Current month (1-12)
    * year ([[USHORT]]) - Current year (1980-2079)
    * timezone ([[SHORT]]) - Minutes west of UTC (Universal Time Coordinate -720 to 720). 
    * weekday ([[UCHAR]]) - Current day of the week. This value is ignored and is calculated from the other parameter information.

===== Return Code =====

rc ([[USHORT]]) - return

Return code descriptions are:

  * 0 NO_ERROR
  *327 ERROR_TS_DATETIME

===== Remarks =====

The value of timezone is the difference in minutes between the current time zone and UTC. This is a positive number if earlier than UTC, and negative number if it is later. For Eastern Standard Time this value is 300 (five hours earlier than UTC).

To get the date and time, issue [[DosGetDateTime]]. If the application is executing in the OS/2 environment, it is more efficient to obtain these variables by calling [[DosGetInfoSeg]] instead of this function. However, applications written to the family API cannot depend on the availability of [[DosGetInfoSeg]].

Not adhering to the limits on any of the parameters results in the return code being set to rc = 327 (ERROR_TS_DATETIME). Also, OS/2 verifies that the day is possible for the month and the year (even for leap year). If the day is not reasonable, OS/2 will also set rc = 327. 

===== Example Code =====

==== C Binding ====

<code c>
typedef struct _DATETIME {  /* date */
  UCHAR   hours;            /* current hour */
  UCHAR   minutes;          /* current minute */
  UCHAR   seconds;          /* current second */
  UCHAR   hundredths;       /* current hundredths of a second */
  UCHAR   day;              /* current day */
  UCHAR   month;            /* current month */
  USHORT  year;             /* current year */
  SHORT   timezone;         /* minutes of time west of UTC */
  UCHAR   weekday;          /* current day of week */
} DATETIME;

#define INCL_DOSDATETIME

USHORT    rc = DosSetDateTime(DateTime);
PDATETIME DateTime;      /* Date/time structure */
USHORT    rc;            /* return code */
</code>

The following example obtains and prints date and time information. It then changes the system date to 5/10/1987 and prints the updated information. 

<code c>
#define INCL_DOSDATETIME
#include <os2.h>

main()
{
  DATETIME   DateTime;       /* Structure to hold date/time info. */
  USHORT     rc;

  rc = DosGetDateTime(&DateTime);     /* Address of d/t structure */
  printf("Today is %d-%d-%d; the time is %d:%d\n", DateTime.month,
         DateTime.day, DateTime.year, DateTime.hours, DateTime.minutes);
  DateTime.day = 10;
  DateTime.month = 5;
  DateTime.year = 1987;
  printf("The new date is %d-%d-%d; the time is %d:%d\n", DateTime.month,
         DateTime.day, DateTime.year, DateTime.hours, DateTime.minutes);
  rc = DosSetDateTime(&DateTime);    /* Address of d/t structure */
  printf("rc is %d\n", rc);
 }
</code>

==== MASM Binding ====

<code c>
DATETIME struc
  date_hours      db  ? ;current hour
  date_minutes    db  ? ;current minute
  date_seconds    db  ? ;current second
  date_hundredths db  ? ;current hundredths of a second
  date_day        db  ? ;current day
  date_month      db  ? ;current month
  date_year       dw  ? ;current year
  date_timezone   dw  ? ;minutes of time west of UTC
  date_weekday    db  ? ;current day of week
DATETIME ends

EXTRN  DosSetDateTime:FAR
INCL_DOSDATETIME    EQU 1

PUSH@  OTHER   DateTime      ;Date/time structure
CALL   DosSetDateTime
</code>

Returns WORD

===== Note =====

Text based on [[http://www.edm2.com/index.php/DosSetDateTime_(Legacy)]]

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