100 lines
3.3 KiB
C
100 lines
3.3 KiB
C
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/***
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*time.c - get current system time
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*
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* Copyright (c) 1989-2001, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* defines time() - gets the current system time and converts it to
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* internal (time_t) format time.
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*
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*Revision History:
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* 06-07-89 PHG Module created, based on asm version
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* 03-20-90 GJF Made calling type _CALLTYPE1, added #include
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* <cruntime.h> and fixed the copyright. Also, cleaned
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* up the formatting a bit.
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* 07-25-90 SBM Removed '32' from API names
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* 10-04-90 GJF New-style function declarator.
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* 12-04-90 SRW Changed to include <oscalls.h> instead of <doscalls.h>
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* 12-06-90 SRW Added _CRUISER_ and _WIN32 conditionals.
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* 05-19-92 DJM ifndef for POSIX build.
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* 03-30-93 GJF Replaced dtoxtime() reference by __gmtotime_t. Also
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* purged Cruiser support.
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* 04-06-93 SKS Replace _CRTAPI* with __cdecl
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* 07-21-93 GJF Converted from using __gmtotime_t and GetSystemTime,
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* to using __loctotime_t and GetLocalTime.
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* 02-13-95 GJF Merged in Mac version.
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* 09-22-95 GJF Obtain and use Win32's DST flag.
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* 10-24-95 GJF GetTimeZoneInformation is *EXPENSIVE* on NT. Use a
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* cache to minimize calls to this API.
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* 12-13-95 GJF Optimization above wasn't working because I had
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* switched gmt and gmt_cache (thanks PhilipLu!)
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* 10-11-96 GJF More elaborate test needed to determine if current
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* time is a DST time.
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* 05-20-98 GJF Get UTC time directly from the system.
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* 05-17-99 PML Remove all Macintosh support.
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*
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*******************************************************************************/
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#ifndef _POSIX_
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#include <cruntime.h>
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#include <time.h>
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#include <internal.h>
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#include <windows.h>
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/*
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* Number of 100 nanosecond units from 1/1/1601 to 1/1/1970
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*/
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#define EPOCH_BIAS 116444736000000000i64
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/*
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* Union to facilitate converting from FILETIME to unsigned __int64
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*/
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typedef union {
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unsigned __int64 ft_scalar;
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FILETIME ft_struct;
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} FT;
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/***
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*time_t time(timeptr) - Get current system time and convert to time_t value.
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*
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*Purpose:
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* Gets the current date and time and stores it in internal (time_t)
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* format. The time is returned and stored via the pointer passed in
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* timeptr. If timeptr == NULL, the time is only returned, not stored in
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* *timeptr. The internal (time_t) format is the number of seconds since
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* 00:00:00, Jan 1 1970 (UTC).
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*
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* Note: We cannot use GetSystemTime since its return is ambiguous. In
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* Windows NT, in return UTC. In Win32S, probably also Win32C, it
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* returns local time.
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*
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*Entry:
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* time_t *timeptr - pointer to long to store time in.
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*
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*Exit:
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* returns the current time.
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*
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*Exceptions:
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*
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*******************************************************************************/
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time_t __cdecl time (
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time_t *timeptr
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)
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{
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time_t tim;
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FT nt_time;
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GetSystemTimeAsFileTime( &(nt_time.ft_struct) );
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tim = (time_t)((nt_time.ft_scalar - EPOCH_BIAS) / 10000000i64);
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if (timeptr)
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*timeptr = tim; /* store time if requested */
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return tim;
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}
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#endif /* _POSIX_ */
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