ReadPrint Failure. How to use it properly
Carlo McKee
ReadPrint API function.
The printer I am using is connected via USB.
Issue:
The ReadPrint function is returning false. The error code retrieved by
GetLastError is 6 (ERR_INVALID_HANDLE).
Before I use ReadPrint I create a printer handle using the OpenPrint API
function which returns true. Immediately after the OpenPrinter returns I
check if my handle is not invalid and is not. Below is a snippet of my
calls.
//The open printer does return true.
if(!OpenPrinter(( (LPTSTR)(pPrinterName)), &hPrinter, NULL ) )
{
DisplayError(GetLastError(),"GetPrinterStatus: OpenPrinter");
return (FALSE);
}
//I check if I have a Valid Handle and I do
if (hPrinter == INVALID_HANDLE_VALUE)
{
DisplayError(GetLastError(), "GetPrinterStatus: hPrinter invalid");
return (FALSE);
}
//Now that Open the printer and I have a handle I use ReadPrint
//This function actually returns false. The GetLastError is 6
(ERR_INVALID_HANDLE)
//But why is invalid handle if the OpenPrinter gave me a valid handle
if (!ReadPrinter(hPrinter, &Status, 16, &bytesRead))
{
DisplayError( GetLastError(), "GetPrinterStatus: ReadPrinter) );
return (FALSE);
}
I am positive I am getting a good handle from the OpenPrinter since I can
use OpenPrinter to write to the printer using the WritePrinter API. I can
successfully print using WritePrinter but fail to ReadPrinter.
Please advice what I may doing wrong or is there any other API to get data
from a printer.
Thank you
Kellie Fitton
Hi,
You can use the following API to retrieve information
about a specified printer:
GetPrinter()
http://msdn.microsoft.com/en-us/library/ms535494(VS.85).aspx
Kellie.
Jeffrey Tan[MSFT]
I have found an internal record discussing on a similar issue.
In the record, our engineer found out through Windows source code that you
can't read from a printer handle, but you can from a printer job handle. So
the trick is to create a Job using StartDocPrinter, then open a handle to
the printer job (which you can obtain by specifying the following syntax
for the printer name in OpenPrinter... "PrinterName,Job xxxx" (where xxxx
is a job id)).
Below is some test code that does this.
#define BUFSIZE 256
BOOL TestReadPrinterWithJob(LPSTR szPrinterName)
{
HANDLE hPrinter = NULL;
HANDLE hPrinterJob = NULL;
DWORD dwBytesRead;
LPVOID lpBytes = NULL;
DOC_INFO_1 dc;
DWORD jobid;
TCHAR jobStr[100];
// Open a handle to the printer.
if (!OpenPrinter(szPrinterName, &hPrinter, NULL))
{
PrintError(GetLastError(), "OpenPrinter");
return FALSE;
}
// We can't read from a printer handle, but we can read from
// a printer job handle, So the trick is to create a Job using
// StartDocPrinter, then open a handle to the printer job...
ZeroMemory(&dc, sizeof(DOC_INFO_1));
dc.pDocName="Dummy job";
jobid = StartDocPrinter(hPrinter,1,(LPSTR)&dc); // start a Doc
if (jobid == 0)
{
ClosePrinter(hPrinter);
PrintError(GetLastError(), "OpenPrinter");
return FALSE;
}
// Open handle to the printer job...
wsprintf(jobStr, "%s,Job %i", szPrinterName, jobid);
if (!OpenPrinter(jobStr, &hPrinterJob, NULL))
{
ClosePrinter(hPrinter);
PrintError(GetLastError(), "OpenPrinter Job");
return FALSE;
}
// Allocate a buffer to read printer data into...
lpBytes = (LPVOID)malloc(BUFSIZE);
if (!lpBytes)
{
PrintError(GetLastError(), "malloc");
ClosePrinter(hPrinter);
ClosePrinter(hPrinterJob);
return FALSE;
}
// Try ReadPrinter...
SetLastError(0);
if (!ReadPrinter(hPrinterJob, lpBytes, BUFSIZE, &dwBytesRead))
{
PrintError(GetLastError(), "ReadPrinter");
ClosePrinter(hPrinter);
ClosePrinter(hPrinterJob);
if (lpBytes)
free(lpBytes);
return FALSE;
}
else
{
printf("%i bytes successfully read by ReadPrinter (%i attempted)\n",
dwBytesRead, BUFSIZE);
}
// Clean up...
ClosePrinter(hPrinterJob);
EndDocPrinter(hPrinter); // end the doc
ClosePrinter(hPrinter);
if (lpBytes)
free(lpBytes);
return TRUE;
}
void PrintError( DWORD dwError, LPCSTR lpString )
{
#define MAX_MSG_BUF_SIZE 512
char *msgBuf;
DWORD cMsgLen;
cMsgLen = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_ALLOCATE_BUFFER | 40, NULL, dwError,
MAKELANGID(0, SUBLANG_ENGLISH_US), (LPTSTR) &msgBuf, MAX_MSG_BUF_SIZE,
NULL);
printf( "%s Error [%d]:: %s\n", lpString, dwError, msgBuf );
LocalFree( msgBuf );
#undef MAX_MSG_BUF_SIZE
}
So, the basic components necessary are a bidi-aware language monitor (i.e.
one that implements ReadPort), the bidi checkbox checked for the printer
properties, and a printer job handle returned from OpenPrinter (which
implies that a job needs to exist).
Before you can do bidirectional printing, you'll need to have a bidi-aware
printer driver and a language monitor (both which are discussed in the DDK
(Driver Development Kit) documentation. The language monitor or port
monitor should already be using SetPrinter() and SetJob() to set the
printer and job status, which can then be read from an application with
GetPrinter() and/or GetJob(). <http://support.microsoft.com/?id=160129>
shows how to read the status, provided the monitor is setting it.
Hope this helps.
Best regards,
Jeffrey Tan
Microsoft Online Community Support
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Jeffrey Tan[MSFT]
Have you reviewed my reply to you? Does it make sense to you? If you still
need any help or have any concern, please feel free to feedback, thanks.
Best regards,
Jeffrey Tan
Microsoft Online Community Support
=========================================
Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
msd...@microsoft.com.
This posting is provided "AS IS" with no warranties, and confers no rights.
Carlo McKee
I tried to reply you but I was getting a bounced. So I did am trying again.
I did review your solution thanks. The problem I have now seems to be
directly with the printer. When I use your method to retrieve dat form the
printer, the all functions wokr but I get 0 bytes back.
Anyway I am working with the manufacture of th eprinter now and I will let
you know if I still have problems.
Hope you get this message now
Carlo
""Jeffrey Tan[MSFT]"" <je...@online.microsoft.com> wrote in message
news:$8330Zv5...@TK2MSFTNGHUB02.phx.gbl...
Jeffrey Tan[MSFT]
Thanks for your feedback.
Yes, since this issue is much the printer driver dependent, contacting the
manufacture company is an effective approach.
Anyway, if you need further help, please feel free to post, thanks.
diegoalc...@gmail.com
Hello, sorry but I'm still a beginner and only work with C#, like
can I run this code please?