Related from: http://www.codeproject.com/useritems/Share_memory_throuth_DLL.asp Generally, each application has its own data segment. This mearn they are independent where two applications use a dll together. But, sometimes, we want to know what other applications are doing. So we want used a shared memory. There are many ways to do so, use a shared DLL section is one of them. Following is the simply step to create a shared memory. 1. Create a DLL project. 2. Create a segment named “.shared”, and create shared members at this section. #pragma data_seg(".shared") char theBuffer[1024] = ""; #pragma data_seg() 3. Define this section as shared. This is defined at TheDll.def file. SECTIONS .shared READ WRITE SHARED