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From: noro@ohara.info.waseda.ac.jp (Hideo Noro)
Newsgroups: comp.os.mach
Subject: shm*() can use on MACH?
Message-ID: <NORO.91May3143921@wsdohr.ohara.info.waseda.ac.jp>
Date: 3 May 91 05:39:21 GMT
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Organization: Ohara Lab., Dept. of Sci. and Eng., Waseda Univ., JAPAN
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Hello. I've been reading this news group for few weeks.

I wanna run some system on MACH2.5 (I use LUNA88K(omron)),
but MACH seems not to support shared memory system calls
(shm{get,at,dt,ctl}).

Does sombody know how to make shm* system calls compatible library,
or where I could anonymous ftp if possible?

The system uses shm* system calls below. So, not full-compatibility
shm* library (or advice how to make that) is welcome.
-------------------
shmget(XVREGION_KEY, 1024, 0666)
shmget(XVREGION_KEY, size, 00666 | IPC_CREAT)
shmat(id, 0, 0)
shmdt(id)
shmctl(id, IPC_RMID, 0)
shmctl(id, IPC_STAT, &buf) /* system references only buf.shm_atime */
-------------------

I don't know much of MACH, but think;

shmget(key, size, 0666 | IPC_CREAT):
           use vm_allocate(target_task, address,
                   sizeof(struct shmid_ds) + size, TRUE),
               vm_inherit(target_task, address,
			       sizeof(struct shmid_ds) + size, VM_INHERIT_SHARE),
           and target_task has some relation to key,
		       returns some number related to address.
           (also check key has already related some address or not.)
shmat(id, 0, 0):
           returns (address + sizeof(struct shmid_ds)).
shmdt(id): nothing to do.
shmctl(id, IPC_STAT, &buf):
           copies sizeof(struct shmid_ds) bytes of memory image
           begin at address.


I don't know if these are correct or not. Since, I'm not sure
target_task can perform like 'key' which is used in shm*.


Any comments are welcome.

Thanks.

----
Hideo Noro
Ohara Lab., Dept. of Sci. and Eng., Waseda Univ., JAPAN
noro@ohara.info.waseda.ac.jp