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From: sysop@upas.UUCP
Newsgroups: comp.unix.questions
Subject: Microport shmcreate
Message-ID: <97@upas.UUCP>
Date: Sun, 10-May-87 20:47:42 EDT
Article-I.D.: upas.97
Posted: Sun May 10 20:47:42 1987
Date-Received: Thu, 14-May-87 06:13:41 EDT
Reply-To: rcw@upas.UUCP (Robert White)
Distribution: na
Organization: UN*X Public Access System, Denver
Lines: 42
Keywords: shmcreate



This line == can of raid.

	Greetings. I have a problem with the shmcreate facility of
Microport Unix 2.2 when attempting to use shared memory to access
the Hercules bit mapped graphics memory. The documentation says to
put the following line in /etc/rc:

	/etc/shmcreate 0xb0000 b0000 32768  /* create a segment whose key is
					    b0000, mapped to physical address
					    b0000, with length 32768 bytes. */


	In the user program, the following code should give me access
to the  shared memory through char * pointer shmaddr:

	extern char *shmat();

	shmid = shmget (0xb8000,32768,0);   /* shmid is an int, large model */

	shmaddr = shmat (shmid, (char *) 0); /* shmaddr is a large model pntr */


	However, in all cases, shmget returns -1 and errno gets set to 

ENOENT. What am I doing wrong? I am remembering to compile using
the large model.
	Any help would be appreciated. Send to me, and I will post summary
to the net. This is my first post ever, if there are mistakes, polite flames
only.


Robert White, Graphics Information Inc.
UUCP: seismo!nbires!hao!scicom!qetzal!rcw

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