Trouble with DllImport syntax calling GetJob() from a printer driver library

Question

I'm trying to call the GetJob() method documented here. I think I'm having problems with the syntax of the routine right now, both calling and defining. I've finally got something to compile which is the following.

[DllImport(
    "winspool.drv",
    EntryPoint = "GetJob",
    SetLastError = true,
    CharSet = CharSet.Ansi,
    ExactSpelling = true,
    CallingConvention = CallingConvention.StdCall)]
private static extern bool GetJob
    ([InAttribute()] IntPtr hPrinter,
    [InAttribute()] Int32 JobId,
    [InAttribute()] Int32 Level,
    [OutAttribute()] out byte[] pJob,
    [InAttribute()] Int32 cbBuf,
    [OutAttribute()] out Int32 pcbNeeded);

    ...
    ...
    ...
    ...

const int BUFFER_SIZE = 250;
int pcbNeeed = 0;

unsafe
{
    byte[] byteBuffer = new byte[BUFFER_SIZE];

    bResult = GetJob(m_PrinterHandle, jobID, 1, out byteBuffer, BUFFER_SIZE, out pcbNeeed);

}

According to the documentation here, it seems I should be able to use a byte[] without any special marshaling code because it is "blittable". In anycase, I get a runtime exception that says:

Unable to find an entry point named 'GetJob' in DLL 'winspool.drv'. at NQBB.Printer.PrintQueueMonitor.PrinterWatcher.GetJob(IntPtr hPrinter, Int32 JobId, Int32 Level, Byte[]& pJob, Int32 cbBuf, Int32& pcbNeeded)

I think I just have some syntax wrong here. Can anyone see the problem?

Note this section in the documentation: "GetJobW (Unicode) and GetJobA (ANSI)". Your use of `ExactSpelling = true` tells dllimport not to append the A. P.S., you'll find people are more willing to help if you don't insult them. — Raymond Chen, Sep 12 '11 at 19:55
Please stop using the term M$ it's really not funny or clever. — David Heffernan, Sep 12 '11 at 20:09

score 2 · Answer 1 · answered Sep 12 '11 at 20:08

2

Stop using ExactSpelling and then you will link to GetJobA or GetJobW as appropriate.

answered Sep 12 '11 at 20:08

David Heffernan

601,492
42
1,072
1,490

This is really good to know too, I didn't even think of that. – Ultratrunks Sep 12 '11 at 20:12

score 1 · Accepted Answer · answered Sep 12 '11 at 19:56

1

Try setting EntryPoint to "GetJobA". GetJob is not actually in the winspool export list...

answered Sep 12 '11 at 19:56

Brad

529
4
8

Wow, that really ticks me off how much time I spent banging my head trying to figure out what I did wrong. >:-< But thank you. – Ultratrunks Sep 12 '11 at 20:12

Trouble with DllImport syntax calling GetJob() from a printer driver library

2 Answers2