### Berkeley DB Reference Guide: Building Berkeley DB for UNIX/POSIX systems |

### Mac OS X

1. When trying to link multiple Berkeley DB language interfaces (for example, Tcl, C++, Java, Python) into a single process, I get "multiple definitions" errors from dyld.

   To fix this problem, set the environment variable MACOSX_DEPLOYMENT_TARGET to 10.3 (or your current version of OS X), and reconfigure and rebuild Berkeley DB from scratch. See the OS X ld(1) and dyld(1) man pages for information about how OS X handles symbol namespaces, as well as undefined and multiply-defined symbols.

2. When trying to use system-backed shared memory on OS X I see failures about "too many open files".

   The default number of shared memory segments on OS X is too low. To fix this problem, edit the file /etc/rc, changing the kern.sysv.shmmax and kern.sysv.shmseg values as follows:

   >     *** /etc/rc.orig        Fri Dec 19 09:34:09 2003
   >     --- /etc/rc     Fri Dec 19 09:33:53 2003
   >     ***************
   >     *** 84,93 ****
   >        # System tuning
   >        sysctl -w kern.maxvnodes=$(echo $(sysctl -n hw.physmem) '33554432 /
   >     512 * 1024 +p'|dc)
   >     ! sysctl -w kern.sysv.shmmax=4194304
   >        sysctl -w kern.sysv.shmmin=1
   >        sysctl -w kern.sysv.shmmni=32
   >     ! sysctl -w kern.sysv.shmseg=8
   >        sysctl -w kern.sysv.shmall=1024
   >        if [ -f /etc/sysctl-macosxserver.conf ]; then
   >              awk '{ if (!-1 && -1) print $1 }' <
   >     /etc/sysctl-macosxserver.conf | while read
   >     --- 84,93 ----
   >        # System tuning
   >        sysctl -w kern.maxvnodes=$(echo $(sysctl -n hw.physmem) '33554432 /
   >     512 * 1024 +p'|dc)
   >     ! sysctl -w kern.sysv.shmmax=134217728
   >        sysctl -w kern.sysv.shmmin=1
   >        sysctl -w kern.sysv.shmmni=32
   >     ! sysctl -w kern.sysv.shmseg=32
   >        sysctl -w kern.sysv.shmall=1024
   >        if [ -f /etc/sysctl-macosxserver.conf ]; then
   >              awk '{ if (!-1 && -1) print $1 }' <
   >     /etc/sysctl-macosxserver.conf | while read

   and then reboot the system.

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