Re: [Boost-users] [shmem] Help with shmem and fixed segments

From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2006-07-12 11:34:05

Hi,

> if somebody could give me a clue as to how to fix the bug about shmem giving
> a segmentation fault when dealing with large (>100MB) fixed named segments I
> would be most grateful.

When are you getting the segmentation fault? When trying to create the 
segment? When connecting to it? 100 MB seems a big shared memory segment 
and all systems have a maximum shared memory segment size,

Googling around, I've found the following commands:

(http://www.unidata.ucar.edu/software/mcidas/2004/users_guide/workstation.html)

Solaris:

more /usr/sbin/sysdef | grep SHMMAX

Linux:

more /proc/sys/kernel/shmmax

For example, googling around I've seen that Macos X has by default 4MB, 
HP-UX 64 MB, AIX 4.x 256MB. In linux I think it's 32MB. In windows, no 
idea. You should take in care that even if you are below the maximum, 
you must have free memory to create that segment in your system.

I don't know if you are hitting your system maximum, (this should fail 
when creating or connecting to a shared memory segment) but most systems 
have a way to change this maximum.

Regards,

Ion