急！我用很多方法获取打印机状态，但状态值status总是0，求高人指点

[jolee2010]

网上说的方法主要是下面两个函数isOutOfPaper和GetJobs的方法，但得到的status总是0。
我的意图是想在打印前检测打印机是否缺纸，求高人指点，万分感谢！


#include "head.h"
#include "Winspool.h"

BOOL isOutOfPaper();

BOOL GetJobs(HANDLE hPrinter, /* Handle to the printer. */

JOB_INFO_2 **ppJobInfo, /* Pointer to be filled. */
int *pcJobs, /* Count of jobs filled. */
DWORD *pStatus); /* Print Queue status. */

BOOL IsPrinterError(HANDLE hPrinter);

int main()
{
//if(isOutOfPaper())
//{
// printf("Is Out Of Paper!\n");
//}
//else
//{
// printf("Is Not Out Of Paper\n");
//}

HANDLE hPrinter=0;
if(!::OpenPrinter(_T("Canon CX 320"),&hPrinter,NULL))
{
printf("can not open printer!\n");
return FALSE;
}

IsPrinterError(hPrinter);

return 0;
}



BOOL isOutOfPaper()
{
HANDLE hPrinter=0;
DWORD dwNeeded=0;
DWORD dwUsed=0;
PRINTER_INFO_2* pPrinterInfo = NULL;
//PRINTER_INFO_6* pPrinterInfo= (PRINTER_INFO_6 *)malloc( 0 );

if(!::OpenPrinter(_T("Canon CX 320"),&hPrinter,NULL))
{
printf("can not open printer!\n");
return FALSE;
}
if(!::GetPrinter(hPrinter,2,NULL,0,&dwNeeded))
{
if(GetLastError() != ERROR_INSUFFICIENT_BUFFER)
return FALSE;
}

pPrinterInfo= (PRINTER_INFO_2 *)malloc( dwNeeded );
if(!(pPrinterInfo))
return FALSE;

if(!::GetPrinter(hPrinter,2,(LPBYTE)pPrinterInfo,dwNeeded,&dwUsed))
{
printf("can not Get Printer!\n");
return FALSE;
}

::ClosePrinter(hPrinter);

if(pPrinterInfo->Status==PRINTER_STATUS_PAPER_OUT)
{
free(pPrinterInfo);
return TRUE;
}
else
{
free(pPrinterInfo);
return FALSE;
}
}


BOOL GetJobs(HANDLE hPrinter, /* Handle to the printer. */

JOB_INFO_2 **ppJobInfo, /* Pointer to be filled. */
int *pcJobs, /* Count of jobs filled. */
DWORD *pStatus) /* Print Queue status. */

{

DWORD cByteNeeded,
nReturned,
cByteUsed;
JOB_INFO_2 *pJobStorage = NULL;
PRINTER_INFO_2 *pPrinterInfo = NULL;

/* Get the buffer size needed. */
if (!GetPrinter(hPrinter, 2, NULL, 0, &cByteNeeded))
{
if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
return FALSE;
}

pPrinterInfo = (PRINTER_INFO_2 *)malloc(cByteNeeded);
if (!(pPrinterInfo))
/* Failure to allocate memory. */
return FALSE;

/* Get the printer information. */
if (!GetPrinter(hPrinter,
2,
(LPBYTE)pPrinterInfo,
cByteNeeded,
&cByteUsed))
{
/* Failure to access the printer. */
free(pPrinterInfo);
pPrinterInfo = NULL;
return FALSE;
}

/* Get job storage space. */
if (!EnumJobs(hPrinter,
0,
pPrinterInfo->cJobs,
2,
NULL,
0,
(LPDWORD)&cByteNeeded,
(LPDWORD)&nReturned))
{
if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
{
free(pPrinterInfo);
pPrinterInfo = NULL;
return FALSE;
}
}

pJobStorage = (JOB_INFO_2 *)malloc(cByteNeeded);
if (!pJobStorage)
{
/* Failure to allocate Job storage space. */
free(pPrinterInfo);
pPrinterInfo = NULL;
return FALSE;
}

ZeroMemory(pJobStorage, cByteNeeded);

/* Get the list of jobs. */
if (!EnumJobs(hPrinter,
0,
pPrinterInfo->cJobs,
2,
(LPBYTE)pJobStorage,
cByteNeeded,
(LPDWORD)&cByteUsed,
(LPDWORD)&nReturned))
{
free(pPrinterInfo);
free(pJobStorage);
pJobStorage = NULL;
pPrinterInfo = NULL;
return FALSE;
}

/*
* Return the information.
*/
*pcJobs = nReturned;
*pStatus = pPrinterInfo->Status;
*ppJobInfo = pJobStorage;
free(pPrinterInfo);

return TRUE;

}

BOOL IsPrinterError(HANDLE hPrinter)
{

JOB_INFO_2 *pJobs;
int cJobs,
i;
DWORD dwPrinterStatus;

/*
* Get the state information for the Printer Queue and
* the jobs in the Printer Queue.
*/
if (!GetJobs(hPrinter, &pJobs, &cJobs, &dwPrinterStatus))
return FALSE;

/*
* If the Printer reports an error, believe it.
*/
if (dwPrinterStatus &
(PRINTER_STATUS_ERROR |
PRINTER_STATUS_PAPER_JAM |
PRINTER_STATUS_PAPER_OUT |
PRINTER_STATUS_PAPER_PROBLEM |
PRINTER_STATUS_OUTPUT_BIN_FULL |
PRINTER_STATUS_NOT_AVAILABLE |
PRINTER_STATUS_NO_TONER |
PRINTER_STATUS_OUT_OF_MEMORY |
PRINTER_STATUS_OFFLINE |
PRINTER_STATUS_DOOR_OPEN))
{
if(dwPrinterStatus==PRINTER_STATUS_PAPER_OUT)
printf("out of paper!\n");
free( pJobs );
return TRUE;
}

/*
* Find the Job in the Queue that is printing.
*/
for (i=0; i < cJobs; i++)
{
if (pJobs[i].Status & JOB_STATUS_PRINTING)
{
/*
* If the job is in an error state,
* report an error for the printer.
* Code could be inserted here to
* attempt an interpretation of the
* pStatus member as well.
*/
if (pJobs[i].Status &
(JOB_STATUS_ERROR |
JOB_STATUS_OFFLINE |
JOB_STATUS_PAPEROUT |
JOB_STATUS_BLOCKED_DEVQ))
{
free( pJobs );
return TRUE;
}
}
}

/*
* No error condition.
*/
free( pJobs );
return FALSE;

}

[快乐鹦鹉]

这个你有没有仔细和网上的例子对照，你的代码是否与其有出入？
太长了，看着眼花。

[MoXiaoRab]

单步，看到哪一行会出现问题

[jolee2010]

代码没问题。pPrinterInfo里已经获取到打印机的一些信息，就是status总是0

[cnzdgs]

PRINTER_STATUS_PAPER_OUT的含义是纸用光了，是打印过程中遇到的错误，在没有执行任何打印操作前是没法检查的。

[cnzdgs]

以我的打印机为例，纸是装在打印机的外部，装纸的地方根本没有检测装置，自然也就无法事先知道是否有纸，只有在走纸的时候发现没有纸进入打印机内部，这时才能判断出缺纸。在使用各种软件的打印功能时，也都是先开始打印，然后才会提示缺纸。

[jolee2010]

回楼上的高人，是不是只能在打印过程中检测缺纸？有没有办法在打印操作前检测缺纸？

[jolee2010]

我明白了，谢谢楼上的高人解答！