path: root/c-user
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authorSebastian Huber <>2021-04-16 08:57:44 +0200
committerSebastian Huber <>2021-04-19 07:17:44 +0200
commit9bf0184a3e0773dc8f466479da548ff6243eff50 (patch)
tree17d627e22d54ce851c1ff5b6bfd5cb5eebcb576c /c-user
parentc-user: Add scheduler glossary terms (diff)
c-user: Document rtems_semaphore_obtain() errors
Update #3993.
Diffstat (limited to 'c-user')
1 files changed, 8 insertions, 0 deletions
diff --git a/c-user/semaphore/directives.rst b/c-user/semaphore/directives.rst
index 54f40a4..7c2a9c8 100644
--- a/c-user/semaphore/directives.rst
+++ b/c-user/semaphore/directives.rst
@@ -525,9 +525,17 @@ scheduler.
There was no semaphore associated with the identifier specified by ``id``.
+ The semaphore uses a priority ceiling and there was no priority ceiling
+ defined for the :term:`home scheduler` of the calling task.
The semaphore could not be obtained immediately.
+ The semaphore uses a priority ceiling and the calling task had a current
+ priority less than the priority ceiling.
Acquiring of the local, binary semaphore by the calling task would have
cased a deadlock.