Import BSDDB 4.7.25 (as of svn r89086)
This commit is contained in:
Zachary Ware
119
docs_src/memp/memp_fget.so
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119
docs_src/memp/memp_fget.so
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m4_comment([$Id: memp_fget.so,v 10.48 2006/09/13 14:30:54 mjc Exp $])
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define(M4PAGELOCAL,
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[memp_fget, DB_MPOOL_CREATE, DB_MPOOL_DIRTY, DB_MPOOL_EDIT,
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DB_MPOOL_LAST, DB_MPOOL_NEW,
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DB_PAGE_NOTFOUND, DB_LOCK_DEADLOCK])
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include(m4/m4.seealso)
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m4_pf_header(m4_ref(memp_fget),
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ifelse(M4API, C_API, [dnl
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int
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DB_MPOOLFILE-__GT__get(DB_MPOOLFILE *mpf,
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db_pgno_t *pgnoaddr, DB_TXN * txnid, u_int32_t flags, void **pagep);
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])
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ifelse(M4API, CXX_API, [dnl
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int
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DbMpoolFile::get(db_pgno_t *pgnoaddr,
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DbTxn *txnid, u_int32_t flags, void **pagep);
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]))
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m4_p([dnl
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The m4_refT(memp_fget) returns pages from the cache.])
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m4_p([dnl
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All pages returned by m4_ref(memp_fget) will be retained (that is,
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m4_italic(pinned)), in the pool until a subsequent call to
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m4_ref(memp_fput).])
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m4_p([The returned page is m4_bold(size_t) type aligned.])
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m4_p([dnl
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Fully or partially created pages have all their bytes set to a nul byte,
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unless the m4_refT(memp_set_clear_len) was called to specify other
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behavior before the file was opened.])
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m4_idefz(DB_PAGE_NOTFOUND)
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m4_return(memp_fget, except, DB_PAGE_NOTFOUND,
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[if the requested page does not exist and m4_ref(DB_MPOOL_CREATE) was
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not set], prev)
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m4_parambegin
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m4_param(flags, [dnl
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m4_sf_or_may
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m4_tagbegin
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m4_tag(m4_idef(DB_MPOOL_CREATE), [dnl
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If the specified page does not exist, create it. In this case, the
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m4_linkpage(memp_register, pgin, pgin) method, if specified, is
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called.])
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m4_tag(m4_idef(DB_MPOOL_DIRTY), [dnl
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The page will be modified and must be written to the source file before
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being evicted from the pool. For files open with the
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m4_ref(DB_MULTIVERSION) flag set, a new copy of the page will be made
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if this is the first time the specified transaction is modifying it.])
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m4_tag(m4_idef(DB_MPOOL_EDIT), [dnl
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The page will be modified and must be written to the source file before
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being evicted from the pool. No copy of the page will be made, regardless
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of the m4_ref(DB_MULTIVERSION) setting. This flag is only intended for
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use in situations where a transaction handle is not available, such as during
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aborts or recovery.])
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m4_tag(m4_idef(DB_MPOOL_LAST), [dnl
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Return the last page of the source file, and copy its page number into
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the memory location to which m4_arg(pgnoaddr) refers.])
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m4_tag(m4_idef(DB_MPOOL_NEW), [dnl
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Create a new page in the file, and copy its page number into the memory
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location to which m4_arg(pgnoaddr) refers. In this case, the
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m4_linkpage(memp_register, pgin, pgin) method, if specified, is
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m4_bold(not) called.])
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m4_tagend
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m4_p([dnl
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The m4_ref(DB_MPOOL_CREATE), m4_ref(DB_MPOOL_LAST), and
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m4_ref(DB_MPOOL_NEW) flags are mutually exclusive.])])
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m4_param_co(pagep, returned page, REF)
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m4_param(pgnoaddr, [dnl
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If the m4_arg(flags) parameter is set to m4_ref(DB_MPOOL_LAST) or
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m4_ref(DB_MPOOL_NEW), the page number of the created page is copied
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into the memory location to which the m4_arg(pgnoaddr) parameter
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refers. Otherwise, the m4_arg(pgnoaddr) parameter is the page to
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create or retrieve.
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m4_p([m4_bold([dnl
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Page numbers begin at 0; that is, the first page in the file is page
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number 0, not page number 1.])])])
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m4_param(txnid, [If the operation is part of an application-specified
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transaction, the m4_arg(txnid) parameter is a transaction handle
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returned from m4_ref(txn_begin); otherwise NULL. A transaction is
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required if the file is open for multiversion concurrency control by
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passing m4_ref(DB_MULTIVERSION) to m4_ref(memp_fopen) and the
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m4_ref(DB_MPOOL_DIRTY), m4_ref(DB_MPOOL_CREATE) or
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m4_ref(DB_MPOOL_NEW) flags were specified. Otherwise it is ignored.])
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m4_paramend
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m4_err(memp_fget,
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EACCES,
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[The m4_ref(DB_MPOOL_DIRTY) or m4_ref(DB_MPOOL_EDIT) flag was set and
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the source file was not opened for writing.],
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EAGAIN,
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[The page reference count has overflowed. (This should never happen
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unless there is a bug in the application.)],
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einval,
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[the m4_ref(DB_MPOOL_NEW) flag was set, and the source file was not
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opened for writing;
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more than one of m4_ref(DB_MPOOL_CREATE), m4_ref(DB_MPOOL_LAST), and
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m4_ref(DB_MPOOL_NEW) was set.],
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m4_ref(DB_LOCK_DEADLOCK),
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[For transactions configured with m4_ref(DB_TXN_SNAPSHOT), the page has
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been modified since the transaction began.],
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memory,
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[cache is full, and no more pages will fit in the pool])
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m4_seealso(DbMpool)
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m4_page_footer
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