59 lines
2.1 KiB
Plaintext
59 lines
2.1 KiB
Plaintext
m4_comment([$Id: mempfile_class.so,v 10.24 2004/08/13 03:38:58 bostic Exp $])
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define(M4PAGELOCAL, DbMpoolFile)
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include(m4/m4.seealso)
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m4_pf_header(m4_ref(DbMpoolFile),
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ifelse(M4API, C_API, [dnl
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typedef struct __db_mpoolfile DB_MPOOLFILE;
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])
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ifelse(M4API, CXX_API, [dnl
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class DbMpoolFile {
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public:
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DB_MPOOLFILE *DbMpoolFile::get_DB_MPOOLFILE();
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const DB_MPOOLFILE *DbMpoolFile::get_const_DB_MPOOLFILE() const;
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...
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};
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]))
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m4_p([dnl
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The memory pool interfaces for the m4_db database environment are
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methods of the m4_ref(DbEnv) handle. The m4_ref(DbEnv) memory pool
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methods and the m4_ref(DbMpoolFile) class provide general-purpose,
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page-oriented buffer management of files. Although designed to work
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with the other m4_ref(Db) classes, they are also useful for more general
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purposes. The memory pools are referred to in this document as simply
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m4_italic(pools).])
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m4_p([dnl
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Pools may be shared between processes. Pools are usually filled by
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pages from one or more files. Pages in the pool are replaced in LRU
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(least-recently-used) order, with each new page replacing the page that
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has been unused the longest. Pages retrieved from the pool using
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m4_ref(memp_fget) are m4_italic(pinned) in the pool until they are
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returned to the control of the buffer pool using the m4_ref(memp_fput)
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method.])
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m4_p([dnl
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The m4_ref(DbMpoolFile) object is the handle for a file in the memory
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pool. The handle is not free-threaded. Once the m4_refT(memp_fclose)
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is called, the handle may not be accessed again, regardless of that
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method's return.])
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ifelse(M4API, CXX_API, [dnl
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m4_p([dnl
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Each m4_ref(DbMpoolFile) object has an associated m4_refc(DbMpoolFile)
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structure, which is used by the underlying implementation of m4_db and
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its C-language API. The DbMpoolFile::get_DB_MPOOLFILE method returns a
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pointer to this struct. Given a const m4_ref(DbMpoolFile) object,
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DbMpoolFile::get_const_DB_MPOOLFILE returns a const pointer to the same
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struct.])
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m4_p([dnl
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These methods may be useful for m4_db applications including both C
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and C++ language software. It should not be necessary to use these
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calls in a purely C++ application.])])
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m4_seealso(DbMpool)
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m4_page_footer
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