DATELIB_AK

    Mydates -  Functions for Informix, UNIX, and Mydate date formats.
This document describes the functions provided and the datatypes
manipulated by the Mydates.c and getdates.y modules.  These include
functions to convert between Informix DATE, Informix DATETIME, various UNIX
date and time formats, and some new date and time formats that these
modules provide.
Idate_t is a 'C' typedef of Informix's DATE data type which stores the
number of days since December 31, 1899 (ie a value of 1 == 1/1/1900):

This library describes four date formats which are useful for various
sorting and processing dates and times, these are:

   Mydate4_t
Date, stored in a long integer, as CCYYMMDD
(ie as CC*1000000 + YY*10000 + MM * 100 + DD)

   Mydate6_t
Date stored as a structure containing 3 shorts MM, DD, & CCYY.

   My_Datetime
Data structure, similar to timeval, which qstores date and time 
accurate to the nearest microsecond (1/10^6).  The
structure contains a Mydate4_t and two longs containing the
number of seconds since midnight and number of microseconds
since the last second.  The structure is kept normalized.
   gdt_t        This is a struct tm plus a nanoseconds field and a timezone.  
Normally UTC/GMT is stored with the timesome set to local 
minutes west of UTC.  Defined in getdateandtime.h.
getdateandtime
The underlying string to date function all the others
use.  Returns a success/error code and fills a gdt_t
structure. 

strtodate4
Convert character string to a Mydate4_t date.  Accepts a
pointer to a char array and returns a Mydate4_t;

strtodate6
Convert character string to a Mydate6_t date.  Accepts a 
pointer to a char array and a pointer to a Mydate6_t to
hold the result.

strtoidate
Convert string in format to Informix DATE type.  Accepts a 
char array and returns a Idate_t.

strtomydt
Convert string to My_Datetime structure.  Accepts a pointer
to a character string and a pointer to a My_Datetime_t to
hold the result.  Uses an enhanced version of the EMACS
getdate function, can convert anything sensible (like
"3 hours ago yesterday" or "1998-05-19 3:15:52.582347").

gdttomydt
Convert gdt_t date/time to My_Datetime_t.

Mydate4to6
Convert Mydate4_t date to a Mydate6_t date.  Accepts a 
pointer to a Mydate6_t to hold the result and a Mydate4_t. 

Mydate6to4
Convert Mydate6_t date to Mydate4_t date.  Accepts a
Mydate6_t and returns a Mydate4_t.

Mydate6toidate
Convert Mydate6_t date to Informix DATE type.  Accepts a 
Mydate6_t and returns an Idate_t.

Mydate4toidate
Convert Mydate4_t date to Informix DATE type.  Accepts a 
Mydate4_t and returns an Idate_t.

idatetoMydate6
Convert Informix DATE type to Mydate6_t date.  Accepts a 
pointer to a Mydate6_t to hold the result and an Idate_t.

idatetoMydate4
Convert Informix DATE type toMydate4_t  date.  Accepts an
Idate_t and returns an Mydate4_t.

idttomydt
Convert Informix DATETIME type to My_Datetime structure.
Accepts a dtime_t and a pointer to a My_Datetime_t to hold
the result.

ivltomydt
Convert Informix INTERVAL type to My_Datetime structure.
Accepts an intrvl_t and a pointer to a My_Datetime_t to
hold the result.  My_Datetime_t is treated as holding an 
interval as a normalized number of centuries, years,
months, days, seconds, microseconds.  Not tested for
non-default precision of the starting range value.

mydttoidt
Convert My_Datetime date to Informix DATETIME type.
Accepts a My_Datetime_t, a pointer to a dtime_t to hold the
result, and an integer containing the encoded precision for
the result.

idatetotime
Convert Informix DATE to UNIX time_t based at midnight.
Accepts and Idate_t and returns a time_t.

timetoidate
Convert Informix UNIX time_t to Informix DATE.  Accepts a
time_t and returns an Idate_t.
    (Note that My_Datetime_t can hold dates after Jan 18, 2038 22:14:07 (UNIX
     max time)

timetomydt
Convert UNIX time_t to My_Datetime_t.  Accepts a time_t and
a pointer to a My_Datetime_t to hold the result.
timevaltomydt
Convert UNIX timeval structure to My_Datetime structure.
Accepts a struct timeval and a pointer to a My_Datetime_t
to hold the result.

mydttotime
Convert My_Datetime structure to UNIX time_t.  Accepts a
My_Datetime_t and a pointer to a time_t to hold the result.

mydttotimeval
Convert My_Datetime structure to UNIX timeval structure.
Accepts a My_Datetime_t and a opinter to a struct timeval
to hold the result.

mydttostr
Convert My_Datetime structure to a String assuming local time.

mydttostrlcl
Convert My_Datetime structure to String assuming My_Datetime 
contains UTC, timezone can be specified. 

*gdt_format
Format a gdt_t in UNIX standard string format as either UTC or
local time. 

gdt_Validate_Tm Validate a tm structure for internal consistency.  (Structures 
produced by some UNIX library functions are not internally 
consistent neccessarily, this checks as mydates assumes the 
gdt_t structure is internally consistent.