topic Re: OPEN VMS C in Operating System - OpenVMS

OPEN VMS C

Rizwan Latheef — Thu, 25 Oct 2007 11:15:39 GMT

How to printf system time time in OPEN VMS C

Re: OPEN VMS C

Martin Vorlaender — Thu, 25 Oct 2007 11:33:49 GMT

You can either use ANSI C functions. like

time_t t = time((time_t)9); printf(asctime(localtime(&t)));

Or you set up a $DESCRIPTOR and call SYS$ASCTIM().

cu,
Martin

Re: OPEN VMS C

Craig A Berry — Thu, 25 Oct 2007 12:25:42 GMT

There is an exmple of calling lib$sys_asctim here:

http://www.eight-cubed.com/examples/framework.php?file=lib_sys_asctim.c

Re: OPEN VMS C

Martin Vorlaender — Thu, 25 Oct 2007 13:44:45 GMT

...and an example for SYS$ASCTIM here:

http://www.eight-cubed.com/examples/framework.php?file=sys_asctim.c

As much as I prefer LIB$ routines when it comes to not using itemlists for just one item to retrieve, in this case and IMHO, $ASCTIM is easier to use.

Re: OPEN VMS C

Claus Olesen — Thu, 25 Oct 2007 19:25:36 GMT

here's another alternative. the order of year and day is the correct one ihmo.
char *timestamp(char *timestamp)
{
int n;
int csec; //centisecs
struct timeval tv;
struct tm *ptm;

gettimeofday(&tv,NULL);
ptm=localtime(&tv.tv_sec);
n=strftime(timestamp,20,"%Y-%m-%d %H:%M:%S",ptm);
csec=tv.tv_usec/10000;
sprintf(timestamp+n,".%2.2d",csec);
return timestamp;
}

here's a hack. with the year and day in the other order.
int szTime[8] = {23,(int)(szTime+2),0};
lib$date_time(szTime);
printf("%s\n",(char*)(szTime+2));

Re: OPEN VMS C

Hoff — Fri, 26 Oct 2007 18:52:43 GMT

>>> How to printf system time time in OPEN VMS C? <<<

Um, the same way you issue a printf for the system time in every other C implementation? This from K&R C forward through to the ANSI C and POSIX C calls and C99.

Others have addressed the direct C coding question.

I'm going to guess that you're wondering about the C/Unix epoch -- which is the same on OpenVMS as implemented on most (all?) other C platforms -- and the use of the native quadword time format, and UTC timekeeping.

I'd tend to use either the C/Unix epoch or the UTC calls if you're working in new code. Which depends on your particular goals and needs.

There are details on time and timekeeping in the OpenVMS FAQ (www.hoffmanlabs.com) and in the C RTL manual (www.hp.com/go/openvms/doc) with the newest C RTL manual now located in the main OpenVMS manual set and not in the C manual shelf.