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Sharing Data with Memory Mapped Files

, 14 Nov 2010 CPOL
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How to use memory mapped files.

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This article shows how two processes can share data with each other with the help of memory mapped files. The example was written using VC++ 6.0


I wanted a flexible way to share data in between two different processes. Memory mapped files have very important role in Windows, as well as in some other operating systems.

Using the code

In this sample application, one process will write some data to a memory mapped file and other processes will then read that data. Here I am using two different instances of the same application to both read from and write data to a memory mapped file.

Creating the memory mapped file and mapping it to memory

DWORD dwError = GetLastError();
if ( ! m_hFileMMF )
 { MessageBox(_T("Creation of file mapping failed"));
 { m_pViewMMFFile = MapViewOfFile(m_hFileMMF,FILE_MAP_ALL_ACCESS,0,0,0); // map all file
    if(! m_pViewMMFFile )
    { MessageBox(_T("MapViewOfFile function failed"));

Writing data to memory mapped file

  if(m_pViewMMFFile )
	lstrcpy( (LPTSTR) m_pViewMMFFile, m_Text);

Reading data from memory mapped file

    lstrcpy(sReadText, (LPCTSTR) m_pViewMMFFile);
    m_ReadText = sReadText;

Points of Interest

I think memory mapped files can solve many problems very easily but people don't use them very often.


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Kumar Sudhir

India India
No Biography provided

Comments and Discussions

GeneralMy vote of 2 PinmemberXTAL25610-Jan-12 19:52 
QuestionHow the... PinmvpDave Kreskowiak14-Nov-10 18:59 
GeneralCheck this too.. PinmemberSreekanth Muralidharan24-Jun-08 2:17 
GeneralA little simplistic PinmemberStuart Dootson16-Apr-07 22:33 
GeneralRe: A little simplistic PinmemberBlake Miller17-Apr-07 8:52 

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