Subject: POSIX named semaphores naming restrictions in sem_open()
To: None <firstname.lastname@example.org>
From: Ian Zagorskih <email@example.com>
Date: 09/09/2004 22:10:30
According to POSIX specification semaphore name is not required to be started
with slash character:
The name argument points to a string naming a semaphore object. It is
unspecified whether the name appears in the file system and is visible to
functions that take pathnames as arguments. The name argument conforms to the
construction rules for a pathname. If name begins with the slash character,
then processes calling sem_open() with the same value of name shall refer to
the same semaphore object, as long as that name has not been removed. If name
does not begin with the slash character, the effect is
implementation-defined. The interpretation of slash characters other than the
leading slash character in name is implementation-defined.
According to /sys/kern/uipc_sem.c NetBSD realization explicitly requires
leading slash character. On the other hand, AFAIU in NetBSD named semaphores
are pure kernel objects and do no have any relations with file system. So,
technically, object name can be composed from any characters in any
variations (except 0x0).
Any ideas why it was done this way ? Probably i'm missing something important.
Please enlight me :)