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32 .\" @(#)mpool.3 8.1 (Berkeley) 6/4/93
34 .TH MPOOL 3 2012-04-26 "" "Linux Programmer's Manual"
37 mpool \- shared memory buffer pool
43 .BI "MPOOL *mpool_open(DBT *" key ", int " fd ", pgno_t " pagesize \
44 ", pgno_t " maxcache );
46 .BI "void mpool_filter(MPOOL *" mp ", void (*pgin)(void *, pgno_t, void *),"
47 .BI " void (*" pgout ")(void *, pgno_t, void *),"
48 .BI " void *" pgcookie );
50 .BI "void *mpool_new(MPOOL *" mp ", pgno_t *" pgnoaddr );
52 .BI "void *mpool_get(MPOOL *" mp ", pgno_t " pgno ", unsigned int " flags );
54 .BI "int mpool_put(MPOOL *" mp ", void *" pgaddr ", unsigned int " flags );
56 .BI "int mpool_sync(MPOOL *" mp );
58 .BI "int mpool_close(MPOOL *" mp );
62 This page documents interfaces provided in glibc up until version 2.1.
63 Since version 2.2, glibc no longer provides these interfaces.
64 Probably, you are looking for the APIs provided by the
69 is the library interface intended to provide page oriented buffer management
71 The buffers may be shared between processes.
75 initializes a memory pool.
78 argument is the byte string used to negotiate between multiple
79 processes wishing to share buffers.
80 If the file buffers are mapped in shared memory, all processes using
81 the same key will share the buffers.
84 is NULL, the buffers are mapped into private memory.
87 argument is a file descriptor for the underlying file, which must be seekable.
90 is non-NULL and matches a file already being mapped, the
96 argument is the size, in bytes, of the pages into which the file is broken up.
99 argument is the maximum number of pages from the underlying file to cache
101 This value is not relative to the number of processes which share a file's
102 buffers, but will be the largest value specified by any of the processes
107 function is intended to make transparent input and output processing of the
111 function is specified, it is called each time a buffer is read into the memory
112 pool from the backing file.
115 function is specified, it is called each time a buffer is written into the
117 Both functions are called with the
119 pointer, the page number and a pointer to the page to being read or written.
125 pointer and an address as arguments.
126 If a new page can be allocated, a pointer to the page is returned and
127 the page number is stored into the
130 Otherwise, NULL is returned and
138 pointer and a page number as arguments.
139 If the page exists, a pointer to the page is returned.
140 Otherwise, NULL is returned and
145 argument is not currently used.
149 unpins the page referenced by
152 must be an address previously returned by
156 The flag value is specified by ORing
157 any of the following values:
160 The page has been modified and needs to be written to the backing file.
163 returns 0 on success and \-1 if an error occurs.
167 writes all modified pages associated with the
172 returns 0 on success and \-1 if an error occurs.
176 function free's up any allocated memory associated with the memory pool
180 written to the backing file.
182 returns 0 on success and \-1 if an error occurs.
186 function may fail and set
188 for any of the errors specified for the library routine
193 function may fail and set
198 The requested record doesn't exist.
204 functions may fail and set
206 for any of the errors specified for the library routines
214 function may fail and set
216 for any of the errors specified for the library routine
221 function may fail and set
223 for any of the errors specified for the library routine