Return to cbt.3 CVS log

Up to [Research Unix] / researchv10no / cmd / btree

Annotation of researchv10no/cmd/btree/cbt.3, revision 1.1.1.1

1.1       root        1: .SH NAME
                      2: bread, bwrite, bopen, bclose, bseek, bkey, bdelete, bfirst, bflush, breclen
                      3: .TH
                      4: cbt(3)
                      5: .SH SYNOPSIS
                      6: .nf
                      7: .B typedef struct { char *mdata; unsigned short mlen; } mbuf;
                      8: .B #include "cbt.h"
                      9: .B bfile *bopen(file, type) char *file;
                     10: .B bseek(bf, key) bfile *bf; mbuf key;
                     11: .B bfirst(bf) bfile *bf;
                     12: .B bclose(bf) bfile *bf;
                     13: .B breclen(bf) bfile *bf;
                     14: .B bread(bf, key, value) bfile *bf; mbuf *key, *value;
                     15: .B bdelete(bf, key) bfile *bf; mbuf key;
                     16: .B bflush(bf) bfile *bf;
                     17: .fi
                     18: .SH DESCRIPTION
                     19: These subroutines are the C interface to B-tree files.
                     20: Load them using
                     21: .I -lcbt.
                     22: The include file contains the definition of
                     23: .I mbuf.
                     24: B-trees may be shared by multiple readers and a single writer, since the effect of a writer's changes
                     25: are not seen until the root of the tree is written back.
                     26: Keys can be no longer than 255 bytes.
                     27: The routines communicate by means of
                     28: a
                     29: .I bfile
                     30: pointer returned by
                     31: .I bopen.
                     32: A B-tree named
                     33: .I file
                     34: corresponds to two
                     35: .UX
                     36: files,
                     37: .I file.T
                     38: and (if the file is not an index)
                     39: .I file.F.
                     40: The
                     41: .I type
                     42: parameter to
                     43: .I bopen
                     44: should be either 0 or 2, as in open (2).
                     45: .br
                     46: .I bclose
                     47: closes a B-tree and (if necessary) rewrites
                     48: its root.
                     49: .br
                     50: .I bflush
                     51: writes the root without closing the B-tree.
                     52: .PP
                     53: The subroutines keep track of a current
                     54: position in each open B-tree.
                     55: When the B-tree is opened the current
                     56: position is just before the first key.
                     57: Calling
                     58: .I bfirst
                     59: has the same effect.
                     60: .I bseek
                     61: makes the current position just before the
                     62: .I key
                     63: and returns FOUND,
                     64: if the key exists in the file,
                     65: or it makes the current position just before
                     66: the next largest key and returns NOTFOUND,
                     67: or, if there is no larger key in the file
                     68: it returns EOF.
                     69: .I bread
                     70: returns the key and value at the current
                     71: position, and advances the current position.
                     72: Note that the arguments to
                     73: .I bread
                     74: are all pointers.
                     75: If either
                     76: .I key
                     77: or
                     78: .I value
                     79: are NULL, the corresponding argument is not returned.
                     80: .I bread stores its results in the buffers
                     81: given in the arguments, and sets the lengths
                     82: of the results in the arguments.
                     83: .I breclen
                     84: returns the length of the value which will
                     85: be returned by the next call to
                     86: .I bread.

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.