控制除WORD外的打印份数

要实现一个小功能：监视所有打印任务，使得每次只能打印一份

思路：使用EnumJobs 函数枚举所有的打印任务，得到打印的份数，如果发现份数不是1就将任务删除

其中要用SetJob把任务删除的话需要有一定的权限。如果打印机的句柄是自己打开的，由于OpenPrinter 函数第三个参数不好设置，

因此决定用API hook的办法。截获 EndDocPrinter函数，在里面实现主要功能

PS：蛋疼的WORD真是恶心，用EnumJobs获取的打印份数始终是1，不知道是怎么回事

主要代码如下：

EndDocPrinter.h

#pragma once

#include "stdafx.h"

typedef
    BOOL (WINAPI * __pfnEndDocPrinter)(
    _In_  HANDLE hPrinter
    );

BOOL WINAPI my_EndDocPrinter(
    _In_  HANDLE hPrinter
    );

extern __pfnEndDocPrinter pfnEndDocPrinter;

EndDocPrinter.cpp:

#include "stdafx.h"
#include <Winspool.h>

BOOL WINAPI my_EndDocPrinter(
                      _In_  HANDLE hPrinter
                   )
{
    BOOL ret = FALSE;
    DWORD cbNeeded = 0, cReturned = 0;
    DWORD actNeeded = 0;
    TCHAR szCopys[MAX_PATH];
    ret = EnumJobs(hPrinter, 0, 127, 2, NULL, 0, &cbNeeded, &cReturned);
    actNeeded = cbNeeded;
    JOB_INFO_2* print_job = new JOB_INFO_2[actNeeded];
    ret = EnumJobs(hPrinter, 0, 127, 2, (LPBYTE)print_job, actNeeded, &cbNeeded, &cReturned);
    for (int i = 0; i < cReturned; i++)
    {
        short num=print_job[i].pDevMode->dmCopies;
        if(num!=1)
        {
            SetJob(hPrinter, print_job[i].JobId,2,(LPBYTE)&(print_job[i]),JOB_CONTROL_DELETE);
        }
    }

    return pfnEndDocPrinter(hPrinter);
}

DllMain中还是用之前的inline HOOK：

// dllmain.cpp : 定义 DLL 应用程序的入口点。
#include "stdafx.h"


__pfnEndDocPrinter pfnEndDocPrinter = (__pfnEndDocPrinter)GetProcAddress(GetModuleHandle(TEXT("Winspool.drv")), "EndDocPrinter"); 

BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
                     )
{
    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
        InlineHook(
            (__pfnEndDocPrinter)GetProcAddress(GetModuleHandle(TEXT("Winspool.drv")), "EndDocPrinter"),
            my_EndDocPrinter,
            (void **)&pfnEndDocPrinter
            );
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
    }
    return TRUE;
}