In View-OS multiple networking stacks are available to processes
at the same time. View-OS supports the msocket(2) system call.
mstack defines the default stack (for each address family) that is used
when msocket refers to a NULL pathname for its stack.
mstack provides also a backward compatibility for all the programs
using the obsolete socket(2) system call.
The stack mountpoint identifies the stack. In ViewOS it is the mountpoint
where the stack was mounted (by mount(2)(8).
In fact the call:
"socket(domain,type,protocol)" 4
is equivalent to:
"msocket(NULL,domain,type protocol)" 4
mstacks changes the default stack for the desired protocol families and
executes the command (by execve(2)).