Checking available system resources

Is there a way to check available system resources prior 
to executing an operation in an application.

I have a mapping application that has an export to JPEG 
function. There are a number of settings with regards to 
resolution and output color palette etc. Often there is a 
limit to what the user can specify before the application 
will crash due to insufficient sytem resources.

Is there anyway to catch this?

Drop a Command button on a Form (Form1) named Command1 and try this;

Private Type MEMORYSTATUS
      dwLength As Long
      dwMemoryLoad As Long
      dwTotalPhys As Long
      dwAvailPhys As Long
      dwTotalPageFile As Long
      dwAvailPageFile As Long
      dwTotalVirtual As Long
      dwAvailVirtual As Long
End Type

Private Enum MemoryType
    AvailableVirtual
    AvailablePhysical
    AvailablePageFile
    TotalVirtual
    TotalPhysical
    TotalPageFile
End Enum

Private Declare Sub GlobalMemoryStatus Lib "kernel32" _
            (lpBuffer As MEMORYSTATUS)

Private Function SystemMemory(ByVal enMemType As MemoryType) As Double

Dim memsts As MEMORYSTATUS
Dim lngMemory As Long

'Retrieve all memory values
GlobalMemoryStatus memsts

Select Case enMemType
    Case MemoryType.AvailablePhysical: lngMemory = memsts.dwAvailPhys
    Case MemoryType.AvailableVirtual:  lngMemory = memsts.dwAvailVirtual
    Case MemoryType.AvailablePageFile: lngMemory = memsts.dwAvailPageFile
    Case MemoryType.TotalPhysical:     lngMemory = memsts.dwTotalPhys
    Case MemoryType.TotalVirtual:      lngMemory = memsts.dwTotalVirtual
    Case MemoryType.TotalPageFile:     lngMemory = memsts.dwTotalPageFile
End Select

'Return the memory
SystemMemory = lngMemory

End Function

Public Function AvailableMemory() As Double
    'Return Value in Megabytes
     AvailableMemory = SystemMemory(AvailablePhysical) +
SystemMemory(AvailablePageFile)
End Function

Public Function TotalMemory() As Double
    'Return Value in Megabytes
    TotalMemory = SystemMemory(TotalPageFile) + SystemMemory(TotalPhysical)
End Function

Public Function PercentMemoryFree() As Double

    PercentMemoryFree = Format(AvailableMemory / TotalMemory * 100, "0#")

End Function

Private Function BytesToMegabytes(Bytes As Double) As Double

  Dim dblAns As Double
  dblAns = (Bytes / 1024) / 1024
  BytesToMegabytes = Format(dblAns, "###,###,##0.00")

End Function

Public Function DisplayMemory()

Dim strMemory As String
strMemory = "Total Physical: " &
BytesToMegabytes(SystemMemory(TotalPhysical)) & "M" & vbNewLine & _
            "Available Physical: " &
BytesToMegabytes(SystemMemory(AvailablePhysical)) & "M" & vbNewLine & _
            "Total Memory: " & BytesToMegabytes(TotalMemory) & "M" &
vbNewLine & _
            "Available Memory: " & BytesToMegabytes(AvailableMemory) & "M" &
vbNewLine & vbNewLine & _
            "Percent Free: " & PercentMemoryFree & "%"

Form1.Print strMemory

End Function

Private Sub Command1_Click()

DisplayMemory

End Sub

-- 
Chris Hanscom
MVP (Visual Basic)
 http://www.**--****.com/ 
Application Design Section
 http://www.**--****.com/ 
------

"Veign" < XXXX@XXXXX.COM > wrote

I just thought I would mention something that struck me as odd:



What are the # and commas for in the Format command?

FWIW, this does the same thing...

Private Function BytesToMegabytes(Bytes As Double) As Double
Const mega = 2 ^ 20
  BytesToMegabytes = Format(Bytes / mega, "0.00")
End Function


;-)
LFS

WRONG.
For a start, you're returning a double, yet you're 
returning the return value of the Format function! WHY?!
Secondly, Format(Bytes / mega, "0.00") does NOT put commas 
in.

Either use

Private Function BytesToMegabytes(Bytes As Double) As 
String
   Dim dblAns As Double
   dblAns = (Bytes / 1024) / 1024
   BytesToMegabytes = Format$(dblAns, "###,###,##0.00")
End Function

or

Private Function BytesToMegabytes(Bytes As Double) As 
Double
   BytesToMegabytes = (Bytes / 1024) / 1024
End Function


you're just crap.

as odd:
Double
Double

>What are the # and commas for in the Format command?

They are necessary because some people like to see 
thousands separators.

"Ben Taylor" < XXXX@XXXXX.COM > wrote

Do you know what look before you leap means?  In this context it means
you should test your theories and verify their results before you offer them
up as fact.  What I posted returns the exact same results as the originally
posted function.  Both of your suggestions return different results than the
original routine.  In that respect:



Is completely correct, regaurdless of whether or not the returned value
was the desired result.

There is no reason to respond favorably to someone who continually
puts out bad information.  No amount of correction seems to get you
to stop your folly.  As a result, I have no desire to offer advice to
someone who has no willingness to learn from his mistakes.  I can
only hope that the people that read your replies will know enough to
consider the source.

LFS

Ben,

WRONG!!!

Since the function is returning a Double, the conversion will remove the formatting.

Try both of the following in the immediate window.

?CDbl(Format$(12345678.90,"0.00"))
?CDbl(Format$(12345678.90,"###,##0.00"))

How many commas are there in the results?  Neither is formatting the results to display the thousands separator.

"It ain't what you don't know that gets you into trouble. It's what you know
for sure that just ain't so."  --- Mark Twain

Larry,
    Your right - Should be returning a string to maintain the comma's or
change the format.....

Thx
-- 
Chris Hanscom
MVP (Visual Basic)
 http://www.**--****.com/ 
Application Design Section
 http://www.**--****.com/ 
------

So it was Serflaten's returning of a double that was 
wrong, not my assertion of the reason behind the ###,##.
The function should have returned a string, as I indicated.

I would have corrected that, had I been in your shoes. 
Posting an edit of a function that tries to return a 
string when it actually returns a double is downright 
sloppy. Posting an edit of a function that tries to return 
a string when it actually returns a double, when you're a 
respected member of the newsgroup whose posts are taken as 
gospel, is downright CRAP, Larry, I'm sorry. 
The fact that it doesn't error doesn't make a blind bit of 
differene - it's {*filter*}code.
No matter how many of your silly sayings you utter and how 
much you put me down, that was CRAP, *total* crap, utter 
{*filter*}sloppiness that would only have been expected of a 
third-rate programmer that doesn't know one datatype from 
another.
Your slagging off of my reputation in an attempt to defend 
your own sloppiness is the act of a coward.


context it means
before you offer them
as the originally
different results than the
Double
returned value
continually
to get you
offer advice to
mistakes.  I can
know enough to

Ben,

WRONG AGAIN.  It was Veign's original routine that returned a Double and Larry made a change to it that still returned a Double.  In
that context the Format statement was irrelevant and the formatting was lost during the conversion to a double.

That being said, within the context of Veign's post, a String should have been returned by the BytesToMegabytes Function.

"It ain't what you don't know that gets you into trouble. It's what you know
for sure that just ain't so."  --- Mark Twain

"Ben Taylor" < XXXX@XXXXX.COM > wrote

You didn't.  I pointed it out because it seemed out of place.
Until Veign indicated that it could have returned a string, you
or I had no way of knowing that it was to be used to convert
a number to a string.  As written it could have been used in
other numerical expressions because it returned a value type.


It could have had a valid purpose in using Format and still
returning a double.  There were no comments to indicate what
its real purpose was.

The purpose of my post was to get Veign to revisit that function
to better align it with its own intended purpose.  That is what I
set out to do, and it worked.  What was your purpose in trying to
belittle my reply?

LFS

Larry,
    Not worth the energy to keep replying to him....

I appreciate your comments.....

-- 
Chris Hanscom
MVP (Visual Basic)
 http://www.**--****.com/ 
Application Design Section
 http://www.**--****.com/ 
------

In the interest of prolonging this argument <g>, and thinking maybe someone here
could tighten this a bit, here's one I use:

   Public Function FormatSize(ByVal Size As Variant, Optional ByVal LongDisplay As
Boolean = False, Optional SignCoercion As Boolean = True) As String
      Dim sRet As String
      Dim nSize As Currency
      Const KB& = 1024
      Const MB& = KB * KB
      Const GB@ = MB * KB
      Const TB@ = GB * KB

      ' ETC: Our own EVIL TYPE COERCION, for use when you *know* your
      ' own data very well, and that the sign-bit should be ignored!
      ' Comment this block out, if coercion shouldn't be supported.
      If Size < 0 Then
         Select Case VarType(Size)
            Case vbInteger
               Size = CLng(Size) + &H10000       '(2^16)
            Case vbLong
               Size = CDbl(Size) + 4294967296#   '(2^32)
         End Select
      End If

      ' Return size of file in kilobytes.
      If Size < KB Then
         sRet = Format(Size, "#,##0") & " byte"
         If Size <> 1 Then sRet = sRet & "s"
      Else
         ' Divide to obtain base number.
         If Size >= TB Then
            nSize = Size / TB
            sRet = " TB"
         ElseIf Size >= GB Then
            nSize = Size / GB
            sRet = " GB"
         ElseIf Size >= MB Then
            nSize = Size / MB
            sRet = " MB"
         Else
            nSize = Size / KB
            sRet = " KB"
         End If
         ' Display with suitable number of decimals.
         If nSize >= 100 Then
            sRet = Format(nSize, "0") & sRet
         ElseIf nSize >= 10 Then
            sRet = Format(nSize, "0.0") & sRet
         Else
            sRet = Format(nSize, "0.00") & sRet
         End If
      End If

      ' Return more detailed string on request.
      If LongDisplay Then
         If Size >= KB Then
            sRet = sRet & " (" & Format(Size, "#,##0") & " bytes)"
         End If
      End If
      FormatSize = sRet
   End Function

Improvements, anyone?  (Substantive improvements, at least. <g>)

Thanks...   Karl
-- 
[Microsoft Basic: 1976-2001, RIP]

: Improvements, anyone?  (Substantive improvements, at least. <g>)

 http://www.**--****.com/ (?)

-- 

Randy Birch
MVP Visual Basic
 http://www.**--****.com/ 
Please respond only to the newsgroups so all can benefit.