Revert to requiring that exec return -1 if there is a problem loading

a program.

diff --git a/doc/userprog.texi b/doc/userprog.texi
index e3771e4e1aaf0f79e089841fa9d6432903737973..884b757c59bafdc56d1990ecc7e67cedc8814c8d 100644 (file)
--- a/doc/userprog.texi
+++ b/doc/userprog.texi
@@ -405,9 +405,9 @@ conditions (usually errors).
 @item SYS_exec
 @itemx pid_t exec (const char *@var{cmd_line})
 Runs the executable whose name is given in @var{cmd_line}, passing any
-given arguments, and returns the new process's program id (pid).  If
-there is an error loading this program, may return pid -1, which
-otherwise should not be a valid id number.
+given arguments, and returns the new process's program id (pid).  Must
+return pid -1, which otherwise should not be a valid program id, if
+there is an error loading this program.
 
 @item SYS_join
 @itemx int join (pid_t @var{pid})