Comment by BobbyTables2
16 hours ago
The QNX approach is also pretty much how the dynamic linker loads shared libraries today in Linux .
“An era of really expensive memory”. That sounds familiar…
16 hours ago
The QNX approach is also pretty much how the dynamic linker loads shared libraries today in Linux .
“An era of really expensive memory”. That sounds familiar…
I think GP was saying that in QNX the spawning process was responsible for dynamically linking it's child process before running it. With Linux, I think it's the spawned process taking care of it's own dynamic linking.
On QNX the process spawning is done by sending a message to the userspace process manager, which creates a new process table entry and queues up its initial thread. When its initial thread gets a timeslice its entry point may be the dynamic loader (as specified in the PT_INTERP segment) which then does all the dynamic linking as the spawned process or it might be some other entry point like with a statically-linked executable.
So on QNX, the spawned process does all the dynamic linking. The spawning process just sends an asynchronous message to the process manager and then gets on with things in a very deterministic manner as befitting a hard realtime system.