It is possible to configure Berkeley DB at run-time so applications can redirect all Berkeley DB calls to underlying library or system call functionality. For example, an application might want Berkeley DB to call debugging memory allocation routines rather than the standard C library interfaces. The following interfaces support this functionality:
db_env_set_func_close db_env_set_func_dirfree db_env_set_func_dirlist db_env_set_func_exists db_env_set_func_free db_env_set_func_fsync db_env_set_func_ioinfo db_env_set_func_malloc db_env_set_func_map db_env_set_func_open db_env_set_func_read db_env_set_func_realloc db_env_set_func_seek db_env_set_func_sleep db_env_set_func_unlink db_env_set_func_unmap db_env_set_func_write db_env_set_func_yield
These interfaces are available only from the Berkeley DB C language API, and are not available from all of the operating systems Berkeley DB supports.
A not-uncommon problem for applications is the new API in Solaris 2.6 for manipulating large files. Because this API was not part of Solaris 2.5, it is difficult to create a single binary that takes advantage of the large file functionality in Solaris 2.6, but still runs on Solaris 2.5. Example code that supports this is included in the Berkeley DB distribution, however, the example code was written using previous versions of the Berkeley DB APIs, and is only useful as an example.
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