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.\" @(#)recno.3 8.5 (Berkeley) 8/18/94
.\"
-.TH RECNO 3 1994-08-18 "" "Linux Programmer's Manual"
+.TH RECNO 3 2017-09-15 "" "Linux Programmer's Manual"
.UC 7
.SH NAME
recno \- record number database access method
.ft R
.fi
.SH DESCRIPTION
+.IR "Note well" :
+This page documents interfaces provided in glibc up until version 2.1.
+Since version 2.2, glibc no longer provides these interfaces.
+Probably, you are looking for the APIs provided by the
+.I libdb
+library instead.
+.PP
The routine
-.I dbopen
+.BR dbopen (3)
is the library interface to database files.
One of the supported file formats is record number files.
The general description of the database access methods is in
.BR dbopen (3),
-this manual page describes only the recno specific information.
+this manual page describes only the recno-specific information.
.PP
The record number data structure is either variable or fixed-length
records stored in a flat-file format, accessed by the logical record
as the cursor, if positioned after record number one, to shift down
one record.
.PP
-The recno access method specific data structure provided to
-.I dbopen
-is defined in the <db.h> include file as follows:
+The recno access-method-specific data structure provided to
+.BR dbopen (3)
+is defined in the
+.I <db.h>
+include file as follows:
.PP
-.nf
+.in +4n
+.EX
typedef struct {
- u_long flags;
- u_int cachesize;
- u_int psize;
- int lorder;
- size_t reclen;
- u_char bval;
- char *bfname;
+ unsigned long flags;
+ unsigned int cachesize;
+ unsigned int psize;
+ int lorder;
+ size_t reclen;
+ unsigned char bval;
+ char *bfname;
} RECNOINFO;
-.fi
+.EE
+.in
.PP
The elements of this structure are defined as follows:
.TP
-flags
-The flag value is specified by
-.IR or 'ing
+.I flags
+The flag value is specified by ORing
any of the following values:
.RS
.TP
-R_FIXEDLEN
+.B R_FIXEDLEN
The records are fixed-length, not byte delimited.
The structure element
.I reclen
.I reclen
bytes long are automatically padded.
.TP
-R_NOKEY
+.B R_NOKEY
In the interface specified by
-.IR dbopen ,
+.BR dbopen (3),
the sequential record retrieval fills in both the caller's key and
data structures.
-If the R_NOKEY flag is specified, the
+If the
+.B R_NOKEY
+flag is specified, the
.I cursor
routines are not required to fill in the key structure.
This permits applications to retrieve records at the end of files without
reading all of the intervening records.
.TP
-R_SNAPSHOT
+.B R_SNAPSHOT
This flag requires that a snapshot of the file be taken when
-.I dbopen
+.BR dbopen (3)
is called, instead of permitting any unmodified records to be read from
the original file.
.RE
.TP
-cachesize
+.I cachesize
A suggested maximum size, in bytes, of the memory cache.
This value is
.B only
advisory, and the access method will allocate more memory rather than fail.
If
.I cachesize
-is 0 (no size is specified) a default cache is used.
+is 0 (no size is specified), a default cache is used.
.TP
-psize
+.I psize
The recno access method stores the in-memory copies of its records
in a btree.
This value is the size (in bytes) of the pages used for nodes in that tree.
If
.I psize
-is 0 (no page size is specified) a page size is chosen based on the
-underlying file system I/O block size.
+is 0 (no page size is specified), a page size is chosen based on the
+underlying filesystem I/O block size.
See
.BR btree (3)
for more information.
.TP
-lorder
+.I lorder
The byte order for integers in the stored database metadata.
The number should represent the order as an integer; for example,
big endian order would be the number 4,321.
If
.I lorder
-is 0 (no order is specified) the current host order is used.
+is 0 (no order is specified), the current host order is used.
.TP
-reclen
+.I reclen
The length of a fixed-length record.
.TP
-bval
+.I bval
The delimiting byte to be used to mark the end of a record for
variable-length records, and the pad character for fixed-length
records.
-If no value is specified, newlines (``\en'') are used to mark the end
+If no value is specified, newlines ("\en") are used to mark the end
of variable-length records and fixed-length records are padded with
spaces.
.TP
-bfname
+.I bfname
The recno access method stores the in-memory copies of its records
in a btree.
-If bfname is non-NULL, it specifies the name of the btree file,
-as if specified as the filename for a dbopen of a btree file.
+If
+.I bfname
+is non-NULL, it specifies the name of the btree file,
+as if specified as the filename for a
+.BR dbopen (3)
+of a btree file.
.PP
-The data part of the key/data pair used by the recno access method
+The data part of the key/data pair used by the
+.I recno
+access method
is the same as other access methods.
The key is different.
The
.I data
field of the key should be a pointer to a memory location of type
.IR recno_t ,
-as defined in the <db.h> include file.
+as defined in the
+.I <db.h>
+include file.
This type is normally the largest unsigned integral type available to
the implementation.
The
specified each time the file is opened.
.PP
In the interface specified by
-.IR dbopen ,
+.BR dbopen (3),
using the
.I put
interface to create a new record will cause the creation of multiple,
.BR dbopen (3)
or the following:
.TP
-[EINVAL]
+.B EINVAL
An attempt was made to add a record to a fixed-length database that
was too large to fit.
.SH BUGS
Only big and little endian byte order is supported.
-.SH "SEE ALSO"
-.BR btree (3)
+.SH SEE ALSO
+.BR btree (3),
.BR dbopen (3),
.BR hash (3),
.BR mpool (3)
-.sp
+.PP
.IR "Document Processing in a Relational Database System" ,
Michael Stonebraker, Heidi Stettner, Joseph Kalash, Antonin Guttman,
Nadene Lynn, Memorandum No. UCB/ERL M82/32, May 1982.
projects / thirdparty / man-pages.git / blobdiff