.\" 1999-11-10: Merged text taken from the page contributed by
.\" Reed H. Petty (rhp@draper.net)
.\"
-.TH VFORK 2 2017-03-13 "Linux" "Linux Programmer's Manual"
+.TH VFORK 2 2017-09-15 "Linux" "Linux Programmer's Manual"
.SH NAME
vfork \- create a child process and block parent
.SH SYNOPSIS
.BR stdio (3)
buffers), but may call
.BR _exit (2).
-
+.PP
As with
.BR fork (2),
the child process created by
.BR vfork ()
call differs only in the treatment of the virtual address space,
as described above.
-
+.PP
Signals sent to the parent
arrive after the child releases the parent's memory
(i.e., after the child terminates
4.3BSD; POSIX.1-2001 (but marked OBSOLETE).
POSIX.1-2008 removes the specification of
.BR vfork ().
-
+.PP
The requirements put on
.BR vfork ()
by the standards are weaker than those put on
from the perspective of the parent process
(e.g., memory changes would be visible in the parent,
but changes to the state of open file descriptors would not be visible).
-
+.PP
When
.BR vfork ()
is called in a multithreaded process,
(See
.BR pthreads (7)
for a description of Linux threading libraries.)
-
+.PP
A call to
.BR vfork ()
is equivalent to calling
with
.I flags
specified as:
-
+.PP
CLONE_VM | CLONE_VFORK | SIGCHLD
.SS History
The
.\" present, but definitely on its way out'.
In 4.4BSD it was made synonymous to
.BR fork (2)
-but NetBSD introduced it again,
-cf.
+but NetBSD introduced it again;
+see
.UR http://www.netbsd.org\:/Documentation\:/kernel\:/vfork.html
.UE .
In Linux, it has been equivalent to