DB_MPOOLFILE->sync()
#include <db.h>
int
DB_MPOOLFILE->sync(DB_MPOOLFILE *mpf); The DB_MPOOLFILE->sync() method writes all modified pages associated with the DB_MPOOLFILE back to the source file. If any of the modified pages are pinned (that is, currently in use), DB_MPOOLFILE->sync() will ignore them.
The DB_MPOOLFILE->sync() method returns a non-zero error value on failure and 0 on success.