4.4BSD/usr/src/lib/libc/db/doc/mpool.3.ps

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/F0 10/Times-Roman@0 SF 174.84(MPOOL\(3\) 1991 MPOOL\(3\))72 48 R/F1 9
/Times-Bold@0 SF -.18(NA)72 84 S(ME).18 E F0(mpool \255 shared memory b)108 96
Q(uf)-.2 E(fer pool)-.25 E F1(SYNOPSIS)72 112.8 Q/F2 10/Times-Bold@0 SF
(#include <db)108 124.8 Q(.h>)-.4 E(#include <mpool.h>)108 136.8 Q(MPOOL *)108
160.8 Q(mpool_open \(DBT *k)108 172.8 Q(ey)-.1 E 2.5(,i)-.55 G
(nt fd, pgno_t pagesize, pgno_t maxcache\);)216.25 172.8 Q -.1(vo)108 196.8 S
(id).1 E(mpool_\214lter \(MPOOL *mp, v)108 208.8 Q(oid \(*pgin\)\(v)-.1 E
(oid *, pgno_t, v)-.1 E(oid *\),)-.1 E -.1(vo)158 220.8 S(id \(*pgout\)\(v).1 E
(oid *, pgno_t, v)-.1 E(oid *\), v)-.1 E(oid *pgcookie\);)-.1 E -.1(vo)108
244.8 S(id *).1 E(mpool_new \(MPOOL *mp, pgno_t *pgnoaddr\);)108 256.8 Q -.1
(vo)108 280.8 S(id *).1 E(mpool_get \(MPOOL *mp, pgno_t pgno, u_int \215ags\);)
108 292.8 Q(int)108 316.8 Q(mpool_put \(MPOOL *mp, v)108 328.8 Q(oid *pgaddr)
-.1 E 2.5(,u)-.92 G(_int \215ags\);)290.62 328.8 Q(int)108 352.8 Q
(mpool_sync \(MPOOL *mp\);)108 364.8 Q(int)108 388.8 Q
(mpool_close \(MPOOL *mp\);)108 400.8 Q F1(DESCRIPTION)72 417.6 Q/F3 10
/Times-Italic@0 SF(Mpool)108 429.6 Q F0 1.013(is the library interf)3.513 F
1.013(ace intended to pro)-.1 F 1.013(vide page oriented b)-.15 F(uf)-.2 E
1.012(fer management of \214les.)-.25 F 1.012(The b)6.012 F(uf)-.2 E(fers)-.25
E(may be shared between processes.)108 441.6 Q .416(The function)108 458.4 R F3
(mpool_open)2.916 E F0 .417(initializes a memory pool.)2.917 F(The)5.417 E F3
-.1(ke)2.917 G(y)-.2 E F0(ar)2.917 E .417(gument is the byte string used to ne)
-.18 F(gotiate)-.15 E .697(between multiple processes wishing to share b)108
470.4 R(uf)-.2 E 3.196(fers. If)-.25 F .696(the \214le b)3.196 F(uf)-.2 E .696
(fers are mapped in shared memory)-.25 F 3.196(,a)-.65 G(ll)534.44 470.4 Q .894
(processes using the same k)108 482.4 R 1.194 -.15(ey w)-.1 H .894
(ill share the b).15 F(uf)-.2 E 3.394(fers. If)-.25 F F3 -.1(ke)3.394 G(y)-.2 E
F0 .895(is NULL, the b)3.395 F(uf)-.2 E .895(fers are mapped into pri)-.25 F
-.25(va)-.25 G(te).25 E(memory)108 494.4 Q 5.116(.T)-.65 G(he)154.406 494.4 Q
F3(fd)2.616 E F0(ar)2.616 E .115(gument is a \214le descriptor for the underly\
ing \214le, which must be seekable.)-.18 F(If)5.115 E F3 -.1(ke)2.615 G(y)-.2 E
F0 .115(is non-)2.615 F(NULL and matches a \214le already being mapped, the)108
506.4 Q F3(fd)2.5 E F0(ar)2.5 E(gument is ignored.)-.18 E(The)108 523.2 Q F3
(pa)3.328 E -.1(ge)-.1 G(size).1 E F0(ar)3.329 E .829
(gument is the size, in bytes, of the pages into which the \214le is brok)-.18
F .829(en up.)-.1 F(The)5.829 E F3(maxcac)3.329 E(he)-.15 E F0(ar)108 535.2 Q
.153(gument is the maximum number of pages from the underlying \214le to cache\
 at an)-.18 F 2.653(yo)-.15 G .153(ne time.)451.308 535.2 R .153(This v)5.153 F
.153(alue is)-.25 F .099(not relati)108 547.2 R .399 -.15(ve t)-.25 H 2.599(ot)
.15 G .099(he number of processes which share a \214le')168.727 547.2 R 2.6(sb)
-.55 G(uf)350.39 547.2 Q .1(fers, b)-.25 F .1(ut will be the lar)-.2 F .1
(gest v)-.18 F .1(alue speci\214ed by)-.25 F(an)108 559.2 Q 2.5(yo)-.15 G 2.5
(ft)129.79 559.2 S(he processes sharing the \214le.)138.4 559.2 Q(The)108 576 Q
F3(mpool_\214lter)3.254 E F0 .754(function is intended to mak)3.254 F 3.254(et)
-.1 G .754(ransparent input and output processing of the pages possi-)301.778
576 R 3.095(ble. If)108 588 R(the)3.095 E F3(pgin)3.095 E F0 .596
(function is speci\214ed, it is called each time a b)3.095 F(uf)-.2 E .596
(fer is read into the memory pool from the)-.25 F .125(backing \214le.)108 600
R .125(If the)5.125 F F3(pgout)2.625 E F0 .125
(function is speci\214ed, it is called each time a b)2.625 F(uf)-.2 E .125
(fer is written into the backing \214le.)-.25 F .276
(Both functions are are called with the)108 612 R F3(pgcookie)2.777 E F0
(pointer)2.777 E 2.777(,t)-.4 G .277
(he page number and a pointer to the page to being)337.27 612 R
(read or written.)108 624 Q .124(The function)108 640.8 R F3(mpool_ne)2.624 E
(w)-.15 E F0(tak)2.624 E .123(es an MPOOL pointer and an address as ar)-.1 F
2.623(guments. If)-.18 F 2.623(an)2.623 G .623 -.25(ew p)457.568 640.8 T .123
(age can be allo-).25 F .944(cated, a pointer to the page is returned and the \
page number is stored into the)108 652.8 R F3(pgnoaddr)3.445 E F0 3.445
(address. Other)3.445 F(-)-.2 E(wise, NULL is returned and errno is set.)108
664.8 Q 1.167(The function)108 681.6 R F3(mpool_g)3.667 E(et)-.1 E F0(tak)3.667
E 1.167(es a MPOOL pointer and a page number as ar)-.1 F 3.666(guments. If)-.18
F 1.166(the page e)3.666 F 1.166(xists, a)-.15 F .686
(pointer to the page is returned.)108 693.6 R .687
(Otherwise, NULL is returned and errno is set.)5.686 F .687
(The \215ags parameter is not)5.687 F(currently used.)108 705.6 Q 1.463
(The function)108 722.4 R F3(mpool_put)3.963 E F0 1.462
(unpins the page referenced by)3.962 F F3(pgaddr)3.962 E F0(.).73 E F3(Pgaddr)
6.462 E F0 1.462(must be an address pre)3.962 F(viously)-.25 E 197.615
(12, September)72 768 R(1)535 768 Q EP
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/F0 10/Times-Roman@0 SF 174.84(MPOOL\(3\) 1991 MPOOL\(3\))72 48 R(returned by)
108 84 Q/F1 10/Times-Italic@0 SF(mpool_g)2.5 E(et)-.1 E F0(or)2.5 E F1
(mpool_ne)2.5 E(w)-.15 E F0 5(.T).31 G(he \215ag v)271.65 84 Q
(alue is speci\214ed by)-.25 E F1(or)2.5 E F0('ing an).73 E 2.5(yo)-.15 G 2.5
(ft)434.74 84 S(he follo)443.35 84 Q(wing v)-.25 E(alues:)-.25 E(MPOOL_DIR)108
100.8 Q(TY)-.6 E
(The page has been modi\214ed and needs to be written to the backing \214le.)
144 112.8 Q F1(Mpool_put)108 129.6 Q F0
(returns 0 on success and -1 if an error occurs.)2.5 E .247(The function)108
146.4 R F1(mpool_sync)2.747 E F0 .247(writes all modi\214ed pages associated w\
ith the MPOOL pointer to the backing \214le.)2.747 F F1(Mpool_sync)108 158.4 Q
F0(returns 0 on success and -1 if an error occurs.)2.5 E(The)108 175.2 Q F1
(mpool_close)2.698 E F0 .198(function free')2.698 F 2.698(su)-.55 G 2.698(pa)
245.432 175.2 S .498 -.15(ny a)257.57 175.2 T .198
(llocated memory associated with the memory pool cookie.).15 F(Modi-)5.197 E
(\214ed pages are)108 187.2 Q/F2 10/Times-Bold@0 SF(not)2.5 E F0
(written to the backing \214le.)2.5 E F1(Mpool_close)5 E F0
(returns 0 on success and -1 if an error occurs.)2.5 E/F3 9/Times-Bold@0 SF
(ERR)72 204 Q(ORS)-.27 E F0(The)108 216 Q F1(mpool_open)2.938 E F0 .438
(function may f)2.938 F .438(ail and set)-.1 F F1(errno)2.938 E F0 .438(for an)
2.938 F 2.938(yo)-.15 G 2.938(ft)344.87 216 S .439
(he errors speci\214ed for the library routine)353.918 216 R F1(mal-)2.939 E
(loc)108 228 Q F0(\(3\).).31 E(The)108 244.8 Q F1(mpool_g)2.5 E(et)-.1 E F0
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(wing:)-.25 E([EINV)108 261.6 Q 29.98(AL] The)-1.35 F(requested record doesn')
2.5 E 2.5(te)-.18 G(xist.)305.96 261.6 Q(The)108 278.4 Q F1(mpool_ne)4.073 E(w)
-.15 E F0(and)4.073 E F1(mpool_g)4.073 E(et)-.1 E F0 1.573(functions may f)
4.073 F 1.573(ail and set)-.1 F F1(errno)4.073 E F0 1.573(for an)4.073 F 4.073
(yo)-.15 G 4.073(ft)421.336 278.4 S 1.573(he errors speci\214ed for the)431.519
278.4 R(library routines)108 290.4 Q F1 -.37(re)2.5 G(ad).37 E F0(\(2\)).77 E
F1 2.5(,w).54 G(rite)214.48 290.4 Q F0(\(2\)).18 E F1(,).54 E F0(and)2.5 E F1
(malloc)2.5 E F0(\(3\).).31 E(The)108 307.2 Q F1(mpool_sync)4.287 E F0 1.787
(function may f)4.287 F 1.787(ail and set)-.1 F F1(errno)4.288 E F0 1.788
(for an)4.288 F 4.288(yo)-.15 G 4.288(ft)356.694 307.2 S 1.788
(he errors speci\214ed for the library routine)367.092 307.2 R F1(write)108
319.2 Q F0(\(2\).).18 E(The)108 336 Q F1(mpool_close)4.125 E F0 1.624
(function may f)4.125 F 1.624(ail and set)-.1 F F1(errno)4.124 E F0 1.624
(for an)4.124 F 4.124(yo)-.15 G 4.124(ft)357.842 336 S 1.624
(he errors speci\214ed for the library routine)368.076 336 R F1(fr)108 348 Q
(ee)-.37 E F0(\(3\).).18 E F3(SEE ALSO)72 364.8 Q F1(dbopen)108 376.8 Q F0
(\(3\),).24 E F1(btr)2.5 E(ee)-.37 E F0(\(3\),).18 E F1(hash)2.5 E F0(\(3\),)
.28 E F1 -.37(re)2.5 G(cno).37 E F0(\(3\)).18 E 197.615(12, September)72 768 R
(2)535 768 Q EP
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