在同一内存空间中打开两个程序

Question

Is it possible to launch two completely independent programs into one scope of memory area?

For example, I have skype.exe and opera.exe and I want to launch them on a way that will allows them to share common memory. Sounds like threading to me.

Answer 1

If they are two independent programs running then you have to ensure that the data is passed in an independent way between them. Let's say the two programs are running, the first program compute some data that the second program needs. The simplest thing to do is print the data from the first program into a file with some status at the end of the file (to indicate that it is safe for the other program to start reading it). From the other program you have a while loop that checks the status of the last line in that file every period of time.

The other option is to use some library like MPI which has protocols for message passing implemented.

Answer 2

These are quite some questions at the same time, let me try to dissect:

• It is the definition of a process on a modern OS to have its own virtual address space. So running two processes in the same address space can't happen without a modification to the OS to allow exactly that.
• Even if such a modification were available, it would be a less than perfect idea: Access to memory shared between threads is governed by synchronisation primitives explicitly built into them. There is no such mechanism to manage memory access between two processes, that have not explicitly been designed so
• Sharing memory if so designed between processes does not at all need them to run in the same virtual address space in their totality: Shared memory segments exist in virtually all modern OS to facilitate exactly that. Again, those processes have to be explicitly designed to use this feature.