vfork - spawn new process and block parent
vfork() was originally used to create new processes without
the address space of the old process, which is horrendously
in a paged environment. It was useful when the purpose of
have been to create a new system context for an execve(2).
is now efficient, even in the above case, the need for
vfork() has diminished.
vfork() differs from fork(2) in that the parent is
the child makes a call to execve(2) or an exit (either
by a call to
_exit(2) or abnormally).
vfork() returns 0 in the child's context and (later) the PID
of the child
in the parent's context.
Same as for fork(2).
execve(2), fork(2), sigaction(2), wait(2)
The vfork() function call appeared in 2.9BSD.
To avoid a possible deadlock situation, processes that are
the middle of a vfork() are never sent SIGTTOU or SIGTTIN
rather, output or ioctl(2) calls are allowed and input attempts result in
an end-of-file indication.
OpenBSD 3.6 June 30, 1997
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