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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1999, 2012 Oracle and/or its affiliates. All rights reserved.
*
* $Id$
*/
#include "db_config.h"
#include "db_int.h"
/*
* __os_is_winnt --
* Return 1 if Windows/NT, otherwise 0.
*
* PUBLIC: int __os_is_winnt __P((void));
*/
int
__os_is_winnt()
{
#ifdef DB_WINCE
return (1);
#else
static int __os_type = -1;
/*
* The value of __os_type is computed only once, and cached to
* avoid the overhead of repeated calls to GetVersion().
*/
if (__os_type == -1) {
if ((GetVersion() & 0x80000000) == 0)
__os_type = 1;
else
__os_type = 0;
}
return (__os_type);
#endif
}
/*
* __os_fs_notzero --
* Return 1 if allocated filesystem blocks are not zeroed.
*/
int
__os_fs_notzero()
{
#ifdef DB_WINCE
return (1);
#else
static int __os_notzero = -1;
OSVERSIONINFO osvi;
/*
* Windows/NT zero-fills pages that were never explicitly written to
* the file. Note however that this is *NOT* documented. In fact, the
* Win32 documentation makes it clear that there are no guarantees that
* uninitialized bytes will be zeroed:
*
* If the file is extended, the contents of the file between the old
* EOF position and the new position are not defined.
*
* Experiments confirm that NT/2K/XP all zero fill for both NTFS and
* FAT32. Cygwin also relies on this behavior. This is the relevant
* comment from Cygwin:
*
* Oops, this is the bug case - Win95 uses whatever is on the disk
* instead of some known (safe) value, so we must seek back and fill
* in the gap with zeros. - DJ
* Note: this bug doesn't happen on NT4, even though the
* documentation for WriteFile() says that it *may* happen on any OS.
*
* We're making a bet, here, but we made it a long time ago and haven't
* yet seen any evidence that it was wrong.
*
* Windows 95/98 and On-Time give random garbage, and that breaks
* Berkeley DB.
*
* The value of __os_notzero is computed only once, and cached to
* avoid the overhead of repeated calls to GetVersion().
*/
if (__os_notzero == -1) {
if (__os_is_winnt()) {
osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
GetVersionEx(&osvi);
if (_tcscmp(osvi.szCSDVersion, _T("RTTarget-32")) == 0)
__os_notzero = 1; /* On-Time */
else
__os_notzero = 0; /* Windows/NT */
} else
__os_notzero = 1; /* Not Windows/NT */
}
return (__os_notzero);
#endif
}
/*
* __os_support_direct_io --
* Check to see if we support direct I/O.
*/
int
__os_support_direct_io()
{
return (1);
}
/*
* __os_support_db_register --
* Return 1 if the system supports DB_REGISTER.
*/
int
__os_support_db_register()
{
#ifdef DB_WINCE
return (0);
#else
return (__os_is_winnt());
#endif
}
/*
* __os_support_replication --
* Return 1 if the system supports replication.
*/
int
__os_support_replication()
{
#ifdef DB_WINCE
return (0);
#else
return (__os_is_winnt());
#endif
}
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