Shared Memory

[Paul Falstad]

pthonda at bgsuvax.UUCP (Killer B) wrote:
>encountering the message "Shmget failed :Invalid argument".I tried to 
>typecast the argumnets to call 'shmget' to the right types but the 
>problem is still persistent. However after going through manuals I figured

That has nothing to do with it, as you probably figured out.  The
program wouldn't have gotten past compilation if typecasting were the
answer.

>out that 'shmget' gives this whenever the programs specifies a 
>shared memory segment size which is less than or greater than the system 
>imposed limits.Could anyone tell me how to get the system information 
>about default allowable shared memory segment sizes.

SunOS #defines the minimum shared memory segment size as SHMMIN, in
/usr/include/sys/shm.h.  Your VAX probably doesn't have this, though.  A
nonportable solution is to do "adb /vmunix" and type "_shminfo+4?X" to
get the minimum page size in hex.  If all else fails, you're probably
not losing much by simply setting your shared memory segment size to
whatever the page size is on your machine.

--
Paul Falstad, pfalstad at phoenix.princeton.edu PLink:HYPNOS GEnie:P.FALSTAD
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