drclark@daisy.waterloo.edu (David R. Clark) (06/03/91)
The following program (actually a slight variation of it) works on one of
our local systems (Sequent). On an M2000 running 4.51 the call to mmap fails
(invalid arguments). Any ideas? What I really want to do is choose an arbitrary
region of memory that does not overlap the current program or data space and then
map data into the region. Until I get the simple version working though, I am stuck.
#include <sys/mman.h>
#include <sys/types.h>
#include <fcntl.h>
main() {
int f;
int t;
char *s;
f = open("AND",O_RDWR,0);
if (f == -1) perror("open");
s = malloc(getpagesize());
if (mmap(s,getpagesize(),PROT_READ|PROT_WRITE,MAP_SHARED,f,0) == -1)
perror("mmap");
printf("%s",s);
}trevc@tecate.mips.com (Trevor Cotton) (06/03/91)
In article <1991Jun3.151307.20857@watdragon.waterloo.edu>, drclark@daisy.waterloo.edu (David R. Clark) writes: |> The following program (actually a slight variation of it) works on one of |> our local systems (Sequent). On an M2000 running 4.51 the call to mmap fails |> (invalid arguments). Any ideas? What I really want to do is choose an arbitrary |> region of memory that does not overlap the current program or data space and then |> map data into the region. Until I get the simple version working though, I am stuck. |> |> #include <sys/mman.h> |> #include <sys/types.h> |> #include <fcntl.h> |> main() { |> |> int f; |> int t; |> char *s; |> |> f = open("AND",O_RDWR,0); |> |> if (f == -1) perror("open"); |> |> s = malloc(getpagesize()); |> if (mmap(s,getpagesize(),PROT_READ|PROT_WRITE,MAP_SHARED,f,0) == -1) |> perror("mmap"); |> printf("%s",s); |> } RISC/os 4.5x supports only a subset of the mmap and munmap system calls. Only mapping of character devices is allowed, and only one device can be mapped by a process. What is "AND" in your example? RISC/os 5.0 will add memory mapped file functionality that operates in accordance with SVR4 semantics. We hope to start beta testing of RISC/os 5.0 around the end of July. -- --trevc-- Trevor Cotton, Sustaining Engineering, MIPS Computer Systems Inc. MS 6-05, 930 DeGuigne Drive, Sunnyvale, CA 94088-3650 Tel: +1 408 524 7286 Fax: +1 408 524 7521 Email: {wyse,ames,decwrl,pyramid}!mips!trevc trevc@mips.com
amir@smsc.sony.com (Amir 806) (06/06/91)
In article <4210@spim.mips.COM> trevc@mips.com writes: >In article <1991Jun3.151307.20857@watdragon.waterloo.edu>, drclark@daisy.waterloo.edu (David R. Clark) writes: >|> The following program (actually a slight variation of it) works on one of >|> our local systems (Sequent). On an M2000 running 4.51 the call to mmap fails >|> (invalid arguments). Any ideas? .... > >RISC/os 4.5x supports only a subset of the mmap and munmap system calls. >Only mapping of character devices is allowed, and only one device can >be mapped by a process. >What is "AND" in your example? AND is any ordinary file I think. Anyway, it does fail on our MIPS box. >RISC/os 5.0 will add memory mapped file functionality that operates in >accordance with SVR4 semantics. > >We hope to start beta testing of RISC/os 5.0 around the end of July. > Good. I just tested this on our SVR4 port and it works fine. -- Amir H. Majidimehr Operating Systems Group Sony Microsystems amir@sony.com | ...!{uunet,mips}!sonyusa!amir
drclark@daisy.uwaterloo.ca (David R. Clark) (06/06/91)
I had responded by email but for those interested, the file AND was a regular file and so not map-able under 4.5x . Thanks again.