Ctime question

[rtnMichael]

Hey guys, if I wanted to get the current time in seconds, how would I do it with Ctime....or maybe I don't even use Ctime. Please help

Thanks
Mike

 

[palbano]

#include <time.h>
#include <stdio.h>

int main(int argc, char* argv[])
{
	time_t tm;
	time(&tm);
	printf("%s\r\n", ctime(&tm));
}

-pete

 

[rtnMichael]

when I run this, I get:
Thu Sep 4 10:45:02 2003

I need the time in seconds only, how would I do that?

I want to delete files after a certain time limit and I do a stat on the file and it gives me it's creation time in seconds (I believe ;o)), so I need to get this current time and compare them.

Thanks
Mike

 

[palbano]

I certainly misread your post. Don’t know what happened there

To get and compare file times you may want to use an OS dependent function and structure. What OS are you on?


-pete

 

[rtnMichael]

I'm running it on a UNIX system terminal

Mike

 

[palbano]

Well that leaves me out

If no one jumps in here soon try the C++: Unix forum: forum208

-pete

 

[rtnMichael]

well, thanks for the help at least....)

Mike

 

[Salem]

> it gives me it's creation time in seconds (I believe ;o)),
Not quite - the result is a time_t which MAY be stored in seconds (and frequently is)
Fortunately, there's a handy way of getting real elapsed seconds from this information.

Anyway, to work out what you want, do this

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <time.h>
#include <stdio.h>

int main ( void ) {
    struct stat sb;
    time_t  now = time(NULL);
    stat( &quot;a.out&quot;, &sb );
    printf( &quot;Seconds since last modification=%f\n&quot;, difftime(now,sb.st_mtime) );
    return 0;
}

 

[rtnMichael]

apparently this version of UNIX doesn't support difftime...any ideas?

Mike

 

[danielhozac]

Try

now - sb.st_mtime

.

//Daniel

 

[rtnMichael]

sweet, works like a charm...thanks

mike

 

[Salem]

> apparently this version of UNIX doesn't support difftime...any ideas?
Then it is woefully broken - its surprising that anything is working.
What error message(s) do you get when compiling my previous code?

 

[rtnMichael]

all it did at the time of compiling is:

ld: Undefined external -
_difftime
ld: output file still contains undefined symbols
ld: (Warning) did not generate an output file

Mike

 

[Salem]

If you do

man difftime

do you get a manual page?

difftime() is an ANSI-C function, so it ought to be available everywhere now.

Can you be more specific about which UNIX operating system you have, and the compiler you have (names and versions).

 

[rtnMichael]

when I do a 'man difftime' it gives me
&quot;no manual entry for difftime.&quot;

I'm running HP-UX version 6.5 on an HP 9000/350 system and I compile with cc

Mike