20030514: including udunits.inc in Fortran90 routine

Bill,

>Date: Wed, 14 May 2003 13:45:56 -0700
>From: Bill Riley <address@hidden>
>Organization: ?
>To: Steve Emmerson <address@hidden>
>Subject: Re: 20030513: including udunits.inc in Fortran90 routine

The above message contained the following:

> Thanks, but before you responded I just went into udunits.inc and 
> changed all the "C" in the first column to "!" and it worked.

Interesting solution.

> Now my next problem is that I don't really know how to call udunits.  I 
> have "time" in hours since 1/1/0000 as a real*8 variable. Here is what I 
> put in my subroutine:
> 
>      unitptr = UTMAKE()
>      ercode = UTCALTIME(time,unitptr,oyear,omonth,oday,ohour,tmin,tsec)
> 
> But I get error=-5 back. Am I setting unitptr wrong? How should I do 
> this? Thanks much.

The error code -5 means that the unit structure passed to UTCALTIME is
invalid. This makes sense because you're basically passing an empty unit
structure that isn't a unit of time. You need to set the unit between
your calls, e.g.,

    unitptr = UTMAKE()
    errcode = UTDEC("hours since 1-01-01", unitptr);
    ercode = UTCALTIME(time,unitptr,oyear,omonth,oday,ohour,tmin,tsec)

Interesting time-origin by the way. I hope you know that there is no
year zero: 1 BCE (alias BC) is immediately followed by 1 CE (alias AD).

Regards,
Steve Emmerson