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From: kxn3796@hertz.njit.edu (Ken Nakata)
Newsgroups: comp.os.386bsd.development
Subject: Re: MMAP() doesn't work for me ?
Keywords: mmap, 386bsd
Message-ID: <1993Jun2.152352.25963@njitgw.njit.edu>
Date: 2 Jun 93 15:23:52 GMT
References: <C7xM5G.3sE@unix.portal.com>
Sender: news@njit.edu
Organization: New Jersey Institute of Technology, Newark, N.J.
Lines: 66
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In article <C7xM5G.3sE@unix.portal.com> chris@shell.portal.com (Chris - Ding) writes:
>
>The configuration is 386bsd 0.1 + 0.2.3.
>
>The command sequence is:
>
>#su
>#ls -l /dev/mem
>crw-r----- 1 root 2, 0 May 31 11:58 /dev/mem
>#a.out
>test ( mmap ) : Invalid argument
>
>
>Can anyone tell me what's wrong with the code ? Or there is a bug in the kernal ?
>Thanks.
>C. Ding
>chris@shell.portal.com
>
>------ Source code for a.out --------
>#include <sys/file.h>
>#include <unistd.h>
>#include <stdio.h>
>#include <ctype.h>
>#include <sys/mman.h>
>
>main()
>{
> caddr_t addr;
> int prot = PROT_WRITE;
> static int fd;
>
> int i;
>
> if ( ( fd = open ( "/dev/mem", O_RDWR ) ) == -1 )
> {
> perror ( "test" );
> exit( 1 );
> }
> addr = mmap ( (caddr_t) 0, len, prot, MAP_FILE, fd, (off_t)0x0 );
> if ( addr == ( caddr_t ) -1 )
> {
> perror ( "test (mmap) " );
> exit ( 1 );
> }
>
> :
> :
> :
> :
>}
>
>--
>Chris Ding
>chris@portal.shell.com
This is because /dev/mem doesn't have support for mmap function.
Could any guru/wizard tell us why it doesn't?
Thanks in advance.
Ken Nakata
--
* I apologize if there are misuses of and/or impolite words or phrases in this
mail or post. They are not intended; I don't fully understand certain words or
each nuance of a phrase. Any corrections for either English compositions or
contents are greatly appreciated. Thank you. Ken Nakata, CIS student, NJIT *