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

SunOS

1. I can't specify the DB_SYSTEM_MEM flag to DB_ENV->open.

   The shmget(2) interfaces are not used on SunOS releases prior to 5.0, even though they apparently exist, because the distributed include files did not allow them to be compiled. For this reason, it will not be possible to specify the DB_SYSTEM_MEM flag those versions of SunOS.

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