When attempting to run the sample code below, VB responds with:
        Compile Error:

        User-defined type may not be passed ByVal

I have scoured the MSDN CD's to no avail...  How do I call this (and
other) Win API's from Visual Basic?

Any help getting off the ground will be greatly appreciated!!!

Systems & Networks
Mississippi State University

Sample code:
-------------------------------------------------------------------------------------

Private Type OSVersionInfo
       dwOSVersionInfoSize As Long
       dwMajorVersion As Long
       dwMinorVersion As Long
       dwBuildNumber As Long
       dwPlatformId As Long
       szCSDVersion As String * 128      '  Maintenance string for PSS
usage
End Type

Private Declare Function GetVersionEx Lib "kernel32" Alias
"GetVersionExA" _
                (ByVal lpVersionInformation As OSVersionInfo) _
        As Long

Private Sub Form_Load()

Dim lresult As Long
Dim lpOSVer As OSVersionInfo

lpOSVer.dwOSVersionInfoSize = 0
lpOSVer.dwMajorVersion = 0
lpOSVer.dwMinorVersion = 0
lpOSVer.dwBuildNumber = 0
lpOSVer.dwPlatformId = 0
lpOSVer.szCSDVersion = String(128, 0)

lresult = GetVersionEx(lpOSVer)

End Sub

Drop the ByVal in the declare .. the API viewer is wrong ...

Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" (lpVersionInformation
As OSVERSIONINFO) As Long

--
Randy Birch, MVP Visual Basic
VBnet, The Visual Basic Developers Resource Centre
http://home.sprynet.com/sprynet/rasanen/vbnet/default.htm

Common Controls Replacement Project
http://www.mvps.org/ccrp

:When attempting to run the sample code below, VB responds with:
:        Compile Error:
:
:        User-defined type may not be passed ByVal
:
:I have scoured the MSDN CD's to no avail...  How do I call this (and
:other) Win API's from Visual Basic?
:
:Any help getting off the ground will be greatly appreciated!!!
:

:Systems & Networks
:Mississippi State University
:
:Sample code:
:-------------------------------------------------------------------------------------
:
:Private Type OSVersionInfo
:       dwOSVersionInfoSize As Long
:       dwMajorVersion As Long
:       dwMinorVersion As Long
:       dwBuildNumber As Long
:       dwPlatformId As Long
:       szCSDVersion As String * 128      '  Maintenance string for PSS
:usage
:End Type
:
:
:Private Declare Function GetVersionEx Lib "kernel32" Alias
:"GetVersionExA" _
:                (ByVal lpVersionInformation As OSVersionInfo) _
:        As Long
:
:
:
:Private Sub Form_Load()
:
:
:Dim lresult As Long
:Dim lpOSVer As OSVersionInfo
:
:
:
:lpOSVer.dwOSVersionInfoSize = 0
:lpOSVer.dwMajorVersion = 0
:lpOSVer.dwMinorVersion = 0
:lpOSVer.dwBuildNumber = 0
:lpOSVer.dwPlatformId = 0
:lpOSVer.szCSDVersion = String(128, 0)
:
:lresult = GetVersionEx(lpOSVer)
:
:
:End Sub
:
:
:

In general, if you see a Win32 function that takes a structure that
begins with a size field, they want you to put the structure size in
that field.

-Mike

To reach me by email, either use the link in my Web site at
www.geary.com, or delete "bitbucket." from my email address.
My apologies for the inconvenience provoked by our friends
the spammers.  <sigh>

PS. Can anyone help me with this code, it is not giving the expected
results. I want the version string to say "Win98 4.10.1650" but instead I
get some *REALLY* long number (see code/picture for details).

PPS. Picture available at http://web.singnet.com.sg/~apesena/gveprob.gif

== Begin code ==
Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" (ByRef
lpVersionInformation As OSVERSIONINFO) As Long

Dim rc as long
Dim lpVersionInfo as OSVERSIONINFO
lpVersionInfo.dwOSVersionSize=Len(lpVersionInfo)
rc=GetVersionEx(lpVersionInfo)
lblPlatform.Caption = lpVersionInfo.dwMajorVersion & "." &
lpVersionInfo.dwMinorVersion & "." & lpVersionInfo.dwBuildNumber

The version no. as you would see is 4.10.[some long number]. The 4.10 part
is understandable as I'm running Win98 but I only want to display the
version of Windows the person is running. How can I do this???

== end code ==

OK, I seem to have gotten a workaround by using  szCSDVersion instead of
dwBuildNumber. But it may change in the future...
--
My e-mail address may have 2 bugs in it; deBUG to reply.

Damit Senanayake
Damit's Home; http://web.singnet.com.sg/~apesena/
ICQ UIN: 6930718

"It's one small step for man, one giant leap for mankind." -- Neil Armstrong

Oh, not to be too nitpicky <g>, but from the point of view of a
Windows C/C++ programmer, the variable name "lpVersionInfo" is a bit
confusing. Traditionally, the "lp" prefix is used to indicate that the
variable is a pointer to the data, not the data itself. So a C/C++
Windows  programmer coding in VB would probably name the variable like
this:

Dim VersionInfo as OSVERSIONINFO

i.e. without the "lp" prefix. Or maybe just:

Dim vi as OSVERSIONINFO

to save some typing. Anything but that "lp" prefix... <g>

Anyway, it's your code, not mine, so feel free to disregard this
unrequested advice... <g>

And now for the OSVERSIONINFO documentation:

OSVERSIONINFO

The OSVERSIONINFO data structure contains operating system version
information. The information includes major and minor version numbers,
a build number, a platform identifier, and descriptive text about the
operating system. This structure is used with the GetVersionEx
function.

typedef struct _OSVERSIONINFO{
    DWORD dwOSVersionInfoSize;
    DWORD dwMajorVersion;
    DWORD dwMinorVersion;
    DWORD dwBuildNumber;
    DWORD dwPlatformId;
    TCHAR szCSDVersion[ 128 ];

dwOSVersionInfoSize
Specifies the size, in bytes, of this data structure. Set this member
to sizeof(OSVERSIONINFO) before calling the GetVersionEx function.

dwMajorVersion
Identifies the major version number of the operating system. For
example, for Windows NT version 3.51, the major version number is 3;
and for Windows NT version 4.0, the major version number is 4.

dwMinorVersion
Identifies the minor version number of the operating system. For
example, for Windows NT version 3.51, the minor version number is 51;
and for Windows NT version 4.0, the minor version number is 0.

dwBuildNumber
Windows NT: Identifies the build number of the operating system.
Windows 95: Identifies the build number of the operating system in the
low-order word. The high-order word contains the major and minor
version numbers.

dwPlatformId
Identifies the operating system platform. This member can be one of
the following values: Value Platform
VER_PLATFORM_WIN32s Win32s on Windows 3.1.  
VER_PLATFORM_WIN32_WINDOWS Win32 on Windows 95 or Windows 98.
For Windows 95, dwMinorVersion is 0.

For Windows 98, dwMinorVersion is 10.

VER_PLATFORM_WIN32_NT Win32 on Windows NT.

szCSDVersion
Windows NT: Contains a null-terminated string, such as "Service Pack
3", that indicates the latest Service Pack installed on the system. If
no Service Pack has been installed, the string is empty.
Windows 95: Contains a null-terminated string that provides arbitrary
additional information about the operating system.

QuickInfo
  Windows NT: Requires version 3.5 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Requires version 1.0 or later.
  Header: Declared in winbase.h.
  Unicode: Defined as Unicode and ANSI structures.

See Also
System Information Overview, System Information Structures,
GetVersionEx

-Mike

To reach me by email, either use the link in my Web site at
www.geary.com, or delete "bitbucket." from my email address.
My apologies for the inconvenience provoked by our friends
the spammers.  <sigh>

The build contains 2 long values that need to be extracted ...

  Dim r As Long
  OSV.OSVSize = Len(OSV)
  r = GetVersionEx(OSV)

  Text1(7) = OSV.dwVerMajor
  Text1(8) = OSV.VerMinor
  Text1(9) = LoWord(OSV.BuildNumber)
  Text1(10) = HiWord(OSV.BuildNumber)

 'Computers's System Info
  Text1(11) = OSV.dwVerMajor & "." & OSV.VerMinor & "." & LoWord(OSV.BuildNumber)

Function LoWord(dw As Long) As Integer

   If dw And &H8000& Then
     LoWord = &H8000 Or (dw And &H7FFF&)
     Else: LoWord = dw And &HFFFF&
   End If

End Function

--
Randy Birch, MVP Visual Basic
VBnet, The Visual Basic Developers Resource Centre
http://home.sprynet.com/sprynet/rasanen/vbnet/default.htm

Common Controls Replacement Project
http://www.mvps.org/ccrp

:>When attempting to run the sample code below, VB responds with:
:>        Compile Error:
:>
:>        User-defined type may not be passed ByVal
:>
:>I have scoured the MSDN CD's to no avail...  How do I call this (and
:>other) Win API's from Visual Basic?
:
:Yes, I know about that too... I crashed into the very same error the first
:time. Even removing ByVal doesn't work. You need to explicitly replace it
:with ByRef. This is a hint: UDT's in Win32 API functions are *almost always*
:passed ByRef. What you might want to do is to either get a copy of the Win32
:API help file & port it manually (not recommended) or find someone's port of
:it.
:
:
:PS. Can anyone help me with this code, it is not giving the expected
:results. I want the version string to say "Win98 4.10.1650" but instead I
:get some *REALLY* long number (see code/picture for details).
:
:
:PPS. Picture available at http://web.singnet.com.sg/~apesena/gveprob.gif
:
:== Begin code ==
:Declare Function GetVersionEx Lib "kernel32" Alias "GetVersionExA" (ByRef
:lpVersionInformation As OSVERSIONINFO) As Long
:
:Dim rc as long
:Dim lpVersionInfo as OSVERSIONINFO
:lpVersionInfo.dwOSVersionSize=Len(lpVersionInfo)
:rc=GetVersionEx(lpVersionInfo)
:lblPlatform.Caption = lpVersionInfo.dwMajorVersion & "." &
:lpVersionInfo.dwMinorVersion & "." & lpVersionInfo.dwBuildNumber
:
:
:The version no. as you would see is 4.10.[some long number]. The 4.10 part
:is understandable as I'm running Win98 but I only want to display the
:version of Windows the person is running. How can I do this???
:
:== end code ==
:
:OK, I seem to have gotten a workaround by using  szCSDVersion instead of
:dwBuildNumber. But it may change in the future...
:--
:My e-mail address may have 2 bugs in it; deBUG to reply.
:
:Damit Senanayake
:Damit's Home; http://web.singnet.com.sg/~apesena/
:ICQ UIN: 6930718
:
:"It's one small step for man, one giant leap for mankind." -- Neil Armstrong
:
:
:
:
:
:
:

[snip]

[more info]

--
My e-mail address may have 2 bugs in it; deBUG to reply.

Damit Senanayake
Damit's Home; http://web.singnet.com.sg/~apesena/
ICQ UIN: 6930718

"It's one small step for man, one giant leap for mankind." -- Neil Armstrong

Damit Senanayake

SBN Members' Free Home Pages: http://freesbn.dyn.ml.org/
Damit's Home; http://web.singnet.com.sg/~apesena/
ICQ UIN: 6930718
SiteBuilder Network Level 2 Member
MSDN Online Member

"It's one small step for man, one giant leap for mankind." -- Neil Armstrong

You can try these. Keep the shift functions around for other times you need
them in VB code.

'-------------------------------------------------------
'   LoWord
'
'   Returns the low word of a DWORD
'-------------------------------------------------------
Private Function LoWord(lngValue As Long) As Long
    LoWord = (lngValue And 65535)
End Function

'-------------------------------------------------------
'   HiWord
'
'   Returns the high word of a DWORD
'-------------------------------------------------------
Private Function HiWord(ByVal lngValue As Long) As Long
    HiWord = RightShift(lngValue, 16)
End Function

'----------------------------------------------------------------------
'   LeftShift
'
'   Since VB does not have a left shift operator.
'   LeftShift(8,2)  is equivalent to 8 << 2
'----------------------------------------------------------------------
Private Function LeftShift(ByVal lNum As Long, ByVal lShift As Long) As Long
    LeftShift = lNum * (2 ^ lShift)
End Function

'----------------------------------------------------------------------
'   RightShift
'
'   Since VB does not have a right shift operator.
'   RightShift(8,2)  is equivalent to 8 >> 2
'----------------------------------------------------------------------
Private Function RightShift(ByVal lNum As Long, ByVal lShift As Long) As
Long
    RightShift = lNum / (2 ^ lShift)
End Function

   OSVERSIONINFO vi;
   vi.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
   GetVersionEx( &vi );

Here, the "&" character says to pass a pointer to vi into the
function. But I didn't name "vi" itself with the "lp" prefix, because
"vi" itself is not a pointer. If this is clear as mud, here's another
example of the same function call coded a bit differently:

   OSVERSIONINFO vi;
   OSVERSIONINFO* lpvi;
   lpvi = &vi;
   lpvi->dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
   GetVersionEx( lpvi );

In this example, "vi" is still an OSVERSIONINFO variable, and "lpvi"
is *a pointer to* an OSVERSIONINFO. So I use the "lp" prefix on it,
but not on "vi" itself.

Now after all that, as I mentioned before, how you name your variables
is your own business, so pile as many grains of salt on all my advice
as you wish... <g> But this will give you an idea of how traditional
Windows programmers use those variable naming conventions...

-Mike

To reach me by email, either use the link in my Web site at
www.geary.com, or delete "bitbucket." from my email address.
My apologies for the inconvenience provoked by our friends
the spammers.  <sigh>