Q39916: Using _dos_findfirst to Get the Time and Date

Article: Q39916
Product(s): See article
Version(s): 5.10   | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | s_quickc | mspl13_c
Last Modified: 30-DEC-1988

The code below illustrates how to extract the time and the date out of
the C run-time function _dos_findfirst. The program prints out the
time and the date of the creation of the file "test".

This information also applies to QuickC.

The time at which the file was last written is returned as a binary
value in a word formatted as follows:

   Bits     Meaning

   0-4      Number of seconds DIVIDED BY TWO
        (to find actual number of seconds, multiply by two)
   5-10     Minutes
   11-15    Hours, based on a 24-hour clock

The date at which the file was last written is returned as a binary
value in a word formatted as follows:

   Bits     Meaning

   0-4      Day of the month
   5-8      Month (1 = January and so on)
   9-15     Number of the year minus 1980

The following is a sample code:

#include <dos.h>
#include <stdio.h>

struct {
  unsigned biseconds: 5;  /* in units of TWO seconds */
  unsigned minutes: 6;
  unsigned hours:   5;
} *ptime;

struct{
  unsigned day:   5;
  unsigned month: 4;
  unsigned year:  7;
} *pdate;

struct find_t c_file;

main()
{
   _dos_findfirst ("test", _A_NORMAL, &c_file);

   system("cls");

   ptime = &c_file.wr_time;
   pdate = &c_file.wr_date;

   printf ("Created at %u:%u:%u",\
            ptime->hours, ptime->minutes, ptime->seconds * 2);
        /* NOTE: seconds are divided by two when stored,
             so we have to multiply by two to get
             the proper value.... */

   printf ("on %u-%u-%u.",\
            pdate->month, pdate->day, pdate->year);
}

The program might produce the following output (depending on when the
file "test" was created):

   Created at 10:32:28 on 12-19-8

Note that the seconds field of the time will always be even.

For more information on function _dos_findfirst, see "Microsoft C 5.1
Optimizing Compiler Run-Time Library Reference," starting on Page 194.

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