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Services vs Directives vs System Calls
- Date: Fri, 18 Apr 2008 08:44:19 -0500
- From: joel.sherrill at OARcorp.com (Joel Sherrill)
- Subject: Services vs Directives vs System Calls
> In the RTEMS POSIX API User's Guide for RTEMS 4.6.6 the API functions
> are separated in three groups (services, directives or system calls).
> Some managers have services (like mutex manager), others have directives
> (like semaphore manager) and only one has system calls (timer manager)
Human inconsistency on the authors part and inconsistency
between various standards.
> In RTEMS C User?s Guide (for classical api), we only find directives
> under each manager.
The RTEID/ORKID standard the Classic API is based upon
uniformly used the word service.
POSIX sometimes refers to them as functions. Sometimes
as APIs. Sometimes as interfaces. I think traditionally
anything in the UNIX man pages section 2 was referred
to as a system call.
I pulled out my printed copy of 1003.1b-1996 and found
the words function, interface, and service in a quick scan.
If someone has a clue what the preferred POSIX term is,
I would be happy to see the manual use it.
> Anyone can explain me what is the difference between this three types of
> API functions?
Nothing really that technically matters.
> rtems-users mailing list
> rtems-users at rtems.com
Joel Sherrill, Ph.D. Director of Research & Development
joel.sherrill at OARcorp.com On-Line Applications Research
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