xnu-4903.270.47.tar.gz

[apple/xnu.git] / bsd / man / man2 / vfork.2

diff --git a/bsd/man/man2/vfork.2 b/bsd/man/man2/vfork.2
index 06e201dfcf29fca763fd1871bab839fcaf4112f9..3a07e996593661a573791757a5825dd854b9aad7 100644 (file)
--- a/bsd/man/man2/vfork.2
+++ b/bsd/man/man2/vfork.2
@@ -42,16 +42,18 @@
 .Sh SYNOPSIS
 .Fd #include <unistd.h>
 .Ft pid_t
-.Fn vfork void
+.Fo vfork
+.Fa void
+.Fc
 .Sh DESCRIPTION
-.Fn Vfork
+.Fn vfork
 can be used to create new processes without fully copying the address
 space of the old process, which is horrendously inefficient in a paged
 environment.  It is useful when the purpose of
 .Xr fork 2
 would have been to create a new system context for an
 .Xr execve .
-.Fn Vfork
+.Fn vfork
 differs from
 .Xr fork
 in that the child borrows the parent's memory and thread of
@@ -62,11 +64,11 @@ or an exit (either by a call to
 or abnormally.)
 The parent process is suspended while the child is using its resources.
 .Pp
-.Fn Vfork
+.Fn vfork
 returns 0 in the child's context and (later) the pid of the child in
 the parent's context.
 .Pp
-.Fn Vfork
+.Fn vfork
 can normally be used just like
 .Xr fork .
 It does not work, however, to return while running in the childs context
@@ -91,13 +93,30 @@ it is wrong to call
 .Xr exit
 since buffered data would then be flushed twice.)
 .Sh SEE ALSO
-.Xr fork 2 ,
 .Xr execve 2 ,
+.Xr fork 2 ,
 .Xr sigaction 2 ,
-.Xr wait 2 ,
-.Sh DIAGNOSTICS
-Same as for
-.Xr fork .
+.Xr wait 2 
+.Sh ERRORS
+The
+.Fn vfork
+system call will fail for any of the reasons described
+in the
+.Xr fork
+man page.
+In addition, it will fail if:
+.Bl -tag -width Er
+.\" ===========
+.It Bq Er EINVAL
+A system call other than
+.Xr _exit()
+or
+.Xr execve()
+(or libc functions that make no system calls other than those)
+is called following calling a
+.Fn vfork
+call.
+.El
 .Sh BUGS
 This system call will be eliminated when proper system sharing
 mechanisms are implemented.