Invoke a function from another running program (EXE) in C/C++

[sureshobabu]

i have a doubt in C++. lets asume A.exe is running and it has two functions A() and B(). i have another program B.exe, which needs to call some functions say A() in A.exe (which is already running).

how can we achieve this, what concept we need to use??

if u have some sample code, or tutorial or forums link, give me those reference.