IsWow64Process function
Applies to: desktop apps only
Determines whether the specified process is running under WOW64.
Syntax
BOOL WINAPI IsWow64Process( __in HANDLE hProcess, __out PBOOL Wow64Process );
Parameters
- hProcess [in]
-
A handle to the process. The handle must have the PROCESS_QUERY_INFORMATION or PROCESS_QUERY_LIMITED_INFORMATION access right. For more information, see Process Security and Access Rights.
Windows Server 2003 and Windows XP: The handle must have the PROCESS_QUERY_INFORMATION access right. - Wow64Process [out]
-
A pointer to a value that is set to TRUE if the process is running under WOW64. If the process is running under 32-bit Windows, the value is set to FALSE. If the process is a 64-bit application running under 64-bit Windows, the value is also set to FALSE.
Return value
If the function succeeds, the return value is a nonzero value.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
Remarks
To compile an application that uses this function, define _WIN32_WINNT as 0x0501 or later. For more information, see Using the Windows Headers.
Examples
For compatibility with operating systems that do not support this function, call GetProcAddress to detect whether IsWow64Process is implemented in Kernel32.dll. If GetProcAddress succeeds, it is safe to call this function. Otherwise, WOW64 is not present. Note that this technique is not a reliable way to detect whether the operating system is a 64-bit version of Windows because the Kernel32.dll in current versions of 32-bit Windows also contains this function.
#include <windows.h>
#include <tchar.h>
typedef BOOL (WINAPI *LPFN_ISWOW64PROCESS) (HANDLE, PBOOL);
LPFN_ISWOW64PROCESS fnIsWow64Process;
BOOL IsWow64()
{
BOOL bIsWow64 = FALSE;
//IsWow64Process is not available on all supported versions of Windows.
//Use GetModuleHandle to get a handle to the DLL that contains the function
//and GetProcAddress to get a pointer to the function if available.
fnIsWow64Process = (LPFN_ISWOW64PROCESS) GetProcAddress(
GetModuleHandle(TEXT("kernel32")),"IsWow64Process");
if(NULL != fnIsWow64Process)
{
if (!fnIsWow64Process(GetCurrentProcess(),&bIsWow64))
{
//handle error
}
}
return bIsWow64;
}
int main( void )
{
if(IsWow64())
_tprintf(TEXT("The process is running under WOW64.\n"));
else
_tprintf(TEXT("The process is not running under WOW64.\n"));
return 0;
}
Requirements
|
Minimum supported client | Windows Vista, Windows XP with SP2 |
|---|---|
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Minimum supported server | Windows Server 2008, Windows Server 2003 with SP1 |
|
Header |
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|
Library |
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DLL |
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See also
Send comments about this topic to Microsoft
Build date: 3/7/2012
#ifdef _WIN64
b_64BitOpSys = TRUE
#else
IsWow64Process(GetCurrentProcess(), &b_64BitOpSys);
#endif
Note: A 32 Bit compiled process runs always as Wow64 process on 64 Bit Windows!
This doesn't work - b_64BitOpSys is ALWAYS TRUE if _WIN64 is defined on the DEVELOPMENT system.
dwOemID As Long
dwPageSize As Long
lpMinimumApplicationAddress As Long
lpMaximumApplicationAddress As Long
dwActiveProcessorMask As Long
dwNumberOrfProcessors As Long
dwProcessorType As Long
dwAllocationGranularity As Long
dwReserved As Long
End Type
Private Declare Function IsWow64Process Lib "kernel32" (ByVal hProcess As Long, ByRef Wow64Process As Long) As Long
Private Declare Function GetCurrentProcess Lib "kernel32" () As Long
Private Declare Sub GetNativeSystemInfo Lib "kernel32" (lpSystemInfo As SYSTEM_INFO)
Private Sub Form_Load()
'KPD-Team 2001
'URL: http://www.allapi.net/
'E-Mail: KPDTeam@Allapi.net
Dim Ret As Long
IsWow64Process GetCurrentProcess, Ret
If Ret = 0 Then
MsgBox "This application is not running on an x86 emulator for a 64-bit computer!"
Else
Dim SysInfo64 As SYSTEM_INFO
GetNativeSystemInfo SysInfo64
MsgBox "Number of processors on your 64-bit system: " + CStr(SysInfo64.dwNumberOrfProcessors)
End If
End Sub
- 9/22/2010
- chint
System.Environment.Is64BitOperatingSystem
System.Environment.Is64BitProcess
- 7/16/2010
- eriklitze
- 7/18/2010
- Thomas Lee
The MSDN example determines if your running under WOW64 this can't be used to determine if the OS is x64 because this entry point exists in Kernel32 XP x32 SP2 +
GetNativeSystemInfo Example VB.NET
Private Const PROCESSOR_ARCHITECTURE_INTEL = 0
Private Const PROCESSOR_ARCHITECTURE_IA64 = 6
Private Const PROCESSOR_ARCHITECTURE_AMD64 = 9
Private Const PROCESSOR_ARCHITECTURE_UNKNOWN = &HFFFF
<StructLayout(LayoutKind.Sequential)> _
Public Structure SYSTEM_INFO
Dim wProcessorArchitecture As Short
Dim wReserved As Short
Dim dwPageSize As Integer
Dim lpMinimumApplicationAddress As IntPtr
Dim lpMaximumApplicationAddress As IntPtr
Dim dwActiveProcessorMask As IntPtr
Dim dwNumberOfProcessors As Integer
Dim dwProcessorType As Integer
Dim dwAllocationGranularity As Integer
Dim wProcessorLevel As Short
Dim wProcessorRevision As Short
End Structure
Declare Auto Sub GetNativeSystemInfo Lib "kernel32.dll" (ByRef lpSystemInfo As SYSTEM_INFO)
Public Shared Function IsPlatformX64() As Boolean
Dim sysInfo As SYSTEM_INFO
Dim osv As OperatingSystem
Dim fOk As Boolean = False
osv = Environment.OSVersion
If osv.Version.Major > 5 Or (osv.Version.Major = 5 And osv.Version.Minor >= 1) Then
GetNativeSystemInfo(sysInfo)
Select Case sysInfo.wProcessorArchitecture
Case PROCESSOR_ARCHITECTURE_IA64, PROCESSOR_ARCHITECTURE_AMD64
fOk = True
End Select
End If
Return fOk
End Function
IntPtr Example VB.NET (AnyCPU compiled)
Public Shared Function IsPlatformX64() As Boolean
Dim fOk As Boolean = False
If IntPtr.Size = 8 Then
fOk = True
End If
Return fOk
End Function
