doc: test-writing-guidelines: tst_record_chidlstatus

Add note about passing -1 as a child pid if you want to wait for any of
the process childrens.

Signed-off-by: Cyril Hrubis <chrubis@suse.cz>

1 files changed, 3 insertions, 0 deletions

diff --git a/doc/test-writing-guidelines.txt b/doc/test-writing-guidelines.txt
index 69b8cb769..2475262c6 100644
--- a/doc/test-writing-guidelines.txt
+++ b/doc/test-writing-guidelines.txt
@@ -645,6 +645,9 @@ void tst_record_childstatus(void (*cleanup)(void), pid_t child);
 This function does a 'waitpid()' on child process and record child process's
 return value into the overall test result.
 
+NOTE: As 'waitpid()' is used you may pass '-1' as the child pid if you
+      want to wait for any of the process children.
+
 2.2.8 Fork() and Parent-child synchronization
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^