name a file by the date

knobby67 · 02-11-2009, 09:11 AM

Hi everyone,
hope someone can help out with this, at present I write data to a debug file, however after some day this starts to get very big. basically what I do is the basic

pFile = fopen ("Debug.txt","a+");

However I'd like to open a new file every day under the date for a title. Is there a way I can create a txt file via the date ie "degug662008.txt" etc.

Thanks

millgates · 02-11-2009, 09:31 AM

have you tried

char filename[20];
sprintf(filename,"debug-%i-%i-%i.txt",year,month,day);
pFile = fopen(filename,"a+");

Hko · 02-11-2009, 10:03 AM

See "man strftime" for a complete example program at the end of the man page.

paulsm4 · 02-11-2009, 10:09 AM

Hi -

Here's an example:

Code:

/*
 * SAMPLE OUTPUT
 * Opening file debug20090211...
 */
#include <stdio.h>
#include <limits.h>
#include <time.h>

int
main (int argc, char *argv[])
{
  char fname[PATH_MAX];
  time_t t = time (NULL);
  struct tm *tm = localtime (&t);
  sprintf (fname, "debug%04d%02d%02d",
    (tm->tm_year + 1900),    /* tm_year: years since 1900 */
    (tm->tm_mon + 1),        /* tm_mon: months since January (0 .. 11) */
    tm->tm_mday );           /* tm_mday: day of month (1 .. 31) */
  printf ("Opening file %s...\n", fname);
  return 0;
}

PS:
You can also conveniently do the same thing from a shell script with the `date +FORMAT` command.

jlinkels · 02-11-2009, 11:28 AM

Personally I don't like to have different file names everyday. You can write to a file with the same name everyday and use logrotate to make sure it doesn't grow out of bounds.

jlinkels

knobby67 · 02-11-2009, 12:53 PM

Thanks everyone.
I need to capture all data so can use logrotate.
Didn't think of sprintf.