寫入 Mailslot

寫入 mailslot 類似于寫入標準磁片檔案。 下列程式碼會使用 CreateFile、 WriteFile和 CloseHandle 函式，將簡短訊息放在 mailslot 中。 郵件會廣播到本機電腦上的 「sample_mailslot」 郵件圖伺服器。 程式碼會根據已建立 mailslot 伺服器的假設運作。

#include <windows.h>
#include <stdio.h>

LPCTSTR SlotName = TEXT("\\\\.\\mailslot\\sample_mailslot");

BOOL WriteSlot(HANDLE hSlot, LPCTSTR lpszMessage)
{
   BOOL fResult; 
   DWORD cbWritten; 
 
   fResult = WriteFile(hSlot, 
     lpszMessage, 
     (DWORD) (lstrlen(lpszMessage)+1)*sizeof(TCHAR),  
     &cbWritten, 
     (LPOVERLAPPED) NULL); 
 
   if (!fResult) 
   { 
      printf("WriteFile failed with %d.\n", GetLastError()); 
      return FALSE; 
   } 
 
   printf("Slot written to successfully.\n"); 

   return TRUE;
}

int main()
{ 
   HANDLE hFile; 

   hFile = CreateFile(SlotName, 
     GENERIC_WRITE, 
     FILE_SHARE_READ,
     (LPSECURITY_ATTRIBUTES) NULL, 
     OPEN_EXISTING, 
     FILE_ATTRIBUTE_NORMAL, 
     (HANDLE) NULL); 
 
   if (hFile == INVALID_HANDLE_VALUE) 
   { 
      printf("CreateFile failed with %d.\n", GetLastError()); 
      return FALSE; 
   } 
 
   WriteSlot(hFile, TEXT("Message one for mailslot."));
   WriteSlot(hFile, TEXT("Message two for mailslot."));

   Sleep(5000);

   WriteSlot(hFile, TEXT("Message three for mailslot."));
 
   CloseHandle(hFile); 
 
   return TRUE;
}

以下是執行此範例時所顯示的輸出，其中包含 從 Mailslot 讀取中顯示的 mailslot伺服器。

Slot written to successfully.
Slot written to successfully.
Slot written to successfully.