int DB_MPOOLFILE->get(DB_MPOOLFILE *mpf, db_pgno_t *pgnoaddr, u_int32_t flags, void **pagep);
The DB_MPOOLFILE->get method copies a pointer to the page with the page number specified by pgnoaddr, from the source file in the DB_MPOOLFILE, into the memory location to which pagep refers. If the page does not exist or cannot be retrieved, DB_MPOOLFILE->get will fail.
Page numbers begin at 0; that is, the first page in the file is page number 0, not page number 1.
The returned page is size_t type aligned.
The flags value must be set to 0 or by bitwise inclusively OR'ing together one or more of the following values:
The DB_MPOOL_CREATE, DB_MPOOL_LAST, and DB_MPOOL_NEW flags are mutually exclusive.
Fully or partially created pages have all their bytes set to a nul byte, unless the DB_MPOOLFILE->set_clear_len method was called to specify other behavior before the file was opened.
All pages returned by DB_MPOOLFILE->get will be retained (that is, pinned), in the pool until a subsequent call to DB_MPOOLFILE->put.
The DB_MPOOLFILE->get method returns a non-zero error value on failure, 0 on success, and returns DB_PAGE_NOTFOUND if the requested page does not exist and DB_MPOOL_CREATE was not set.
The DB_MPOOLFILE->get method may fail and return a non-zero error for the following conditions:
The DB_MPOOL_NEW flag was set, and the source file was not opened for writing.
More than one of DB_MPOOL_CREATE, DB_MPOOL_LAST, and DB_MPOOL_NEW was set.
The DB_MPOOLFILE->get method may fail and return a non-zero error for errors specified for other Berkeley DB and C library or system functions. If a catastrophic error has occurred, the DB_MPOOLFILE->get method may fail and return DB_RUNRECOVERY, in which case all subsequent Berkeley DB calls will fail in the same way.
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