Clarify "invalid PID".

Thanks to "Kevin Hart" <kevin.hart@hp.com> for question.

diff --git a/doc/userprog.texi b/doc/userprog.texi
index 7322dd52946c2c9b601063bc717dbd2f38d245cf..00c0f67e21740c550ca2c0d44ae782ebd7b597d1 100644 (file)
--- a/doc/userprog.texi
+++ b/doc/userprog.texi
@@ -594,7 +594,7 @@ the program cannot load or run for any reason.
 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 (i.e.@: killed due to an exception).  If
-@var{pid} is invalid or if it was not a child of the
+@var{pid} is 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.