EnumJobs API Call

[John Fritch]

With two print jobs queued, the first Win32 API call to EnumJobs, shown below,

retval = EnumJobs(hPrinter, 0, 100, 2, ByVal 0, 0, needed, numitems)

returns retval = 1 and needed = numitems = 0. It should have returned retval = 0, numitems = 2, and needed = a non-zero number of bytes needed in the byte buffer to be filled with Job_Info_2 data during the second call to EnumJobs. What gives? I’m running vanilla VB 6 SP4 on Windows 95 and have a single printer, an Epson Color Stylus 600. The api calls correctly identify the name of my printer, and the hwnd value returned for the printer (hPrinter = 5308460) appears to be correct.

I’m also experiencing a similar problem with GetPrinter, for which I am never able to get a cJobs return value of anything other than zero.

John Fritch

[Frans C]

I just tried this function, and it returns the number of printjobs in my printers queue. However, I don't really see an error in your code, providing that the line of code you supplied it supposed to return the error (0) and the buffersize needed.

Private Function EnumPrintJobs(ByVal hPrinter As Long) As Long
Dim retVal As Long
Dim BufNeeded As Long
Dim Returned As Long
Dim Buffer() As Byte
    ' we expect an error here if there are jobs in the queue,
    ' but we need to know the buffersize needed
    retVal = EnumJobs(hPrinter, 0, &HFFFFFFFF, 1, 0, 0, BufNeeded, Returned)
    If retVal = 0 Then
        If Err.LastDllError = ERROR_INSUFFICIENT_BUFFER Then
            ReDim Buffer(BufNeeded)
            retVal = EnumJobs(hPrinter, 0, &HFFFFFFFF, 1, Buffer(0), BufNeeded, BufNeeded, Returned)
            EnumPrintJobs = Returned
        Else
            MsgBox "There is an error getting Printerinformation"
            EnumPrintJobs = 0
        End If
    Else
        EnumPrintJobs = 0
    End If

End Function

[John Fritch]

Frans,

Thanks for the reply. I have a follow-up thread, "Can Printer Software Usurp EnumJobs and GetPrinter?" which you might want to check out.

John Fritch