The Solaris forkall(2) function duplicates the address space and all the threads in the child. Address space duplication is useful, for example, when the child process never calls exec(2) but does use its copy of the parent address space.
When one thread in a process calls Solaris forkall(2), threads that are blocked in an interruptible system call will return EINTR.
Be careful not to create locks that are held by both the parent and child processes. Locks held in both parent and child processes occur when locks are allocated in shared memory by calling mmap() with the MAP_SHARED flag. This problem does not occur if the fork-one model is used.