From: Ben Pfaff Date: Sun, 11 Feb 2007 04:44:25 +0000 (+0000) Subject: Clarify description of "wait" syscall. Thanks to Evan Kutter X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f7b3d255c77f6072e0a930dcc1442e0dff60aba1;p=pintos-anon Clarify description of "wait" syscall. Thanks to Evan Kutter for describing the issue. --- diff --git a/doc/userprog.texi b/doc/userprog.texi index b50dc36..88d8bbd 100644 --- a/doc/userprog.texi +++ b/doc/userprog.texi @@ -619,10 +619,11 @@ the program cannot load or run for any reason. @end deftypefn @deftypefn {System Call} int wait (pid_t @var{pid}) -Waits for process @var{pid} to die and returns the status it passed to -@code{exit}. Returns -1 if @var{pid} -was terminated by the kernel (e.g.@: killed due to an exception). If -@var{pid} is does not refer to a child of the +If process @var{pid} is still alive, waits until it dies. +Then, returns the status that @var{pid} passed to @code{exit}, +or -1 if @var{pid} +was terminated by the kernel (e.g.@: killed due to an exception).= If +@var{pid} does not refer to a child of the calling thread, or if @code{wait} has already been successfully called for the given @var{pid}, returns -1 immediately, without waiting.