.TH "mdb" 3 "Wed Aug 16 2023" "LMDB" \" -*- nroff -*-
.ad l
.nh
.SH NAME
mdb \- LMDB API
.PP
 \- OpenLDAP Lightning Memory-Mapped Database Manager\&.  

.SH SYNOPSIS
.br
.PP
.SS "Modules"

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.RI "\fBVersion Macros\fP"
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.RI "\fBEnvironment Flags\fP"
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.RI "\fBDatabase Flags\fP"
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.RI "\fBWrite Flags\fP"
.br
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.SS "Data Structures"

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.RI "struct \fBMDB_val\fP"
.br
.RI "Generic structure used for passing keys and data in and out of the database\&. "
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.SS "Typedefs"

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.RI "typedef unsigned int \fBMDB_dbi\fP"
.br
.RI "A handle for an individual database in the DB environment\&. "
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.RI "typedef int() \fBMDB_cmp_func\fP(const \fBMDB_val\fP *a, const \fBMDB_val\fP *b)"
.br
.RI "A callback function used to compare two keys in a database\&. "
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.RI "typedef void() \fBMDB_rel_func\fP(\fBMDB_val\fP *item, void *oldptr, void *newptr, void *relctx)"
.br
.RI "A callback function used to relocate a position-dependent data item in a fixed-address database\&. "
.in -1c
.SH "Detailed Description"
.PP 
OpenLDAP Lightning Memory-Mapped Database Manager\&. 


.SH "Data Structure Documentation"
.PP 
.SH "struct MDB_val"
.PP 
Generic structure used for passing keys and data in and out of the database\&. 

Values returned from the database are valid only until a subsequent update operation, or the end of the transaction\&. Do not modify or free them, they commonly point into the database itself\&.
.PP
Key sizes must be between 1 and \fBmdb_env_get_maxkeysize()\fP inclusive\&. The same applies to data sizes in databases with the \fBMDB_DUPSORT\fP flag\&. Other data items can in theory be from 0 to 0xffffffff bytes long\&. 
.PP
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.RI "\fBData Fields\fP"
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.RI "size_t \fBmv_size\fP"
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.RI "void * \fBmv_data\fP"
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.in -1c
.SH "Typedef Documentation"
.PP 
.SS "typedef void() MDB_rel_func(\fBMDB_val\fP *item, void *oldptr, void *newptr, void *relctx)"

.PP
A callback function used to relocate a position-dependent data item in a fixed-address database\&. The \fBnewptr\fP gives the item's desired address in the memory map, and \fBoldptr\fP gives its previous address\&. The item's actual data resides at the address in \fBitem\fP\&. This callback is expected to walk through the fields of the record in \fBitem\fP and modify any values based at the \fBoldptr\fP address to be relative to the \fBnewptr\fP address\&. 
.PP
\fBParameters\fP
.RS 4
\fIitem\fP The item that is to be relocated\&. 
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\fIoldptr\fP The previous address\&. 
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\fInewptr\fP The new address to relocate to\&. 
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\fIrelctx\fP An application-provided context, set by \fBmdb_set_relctx()\fP\&. 
.RE
.PP
\fBTodo\fP
.RS 4
This feature is currently unimplemented\&. 
.RE
.PP

.SH "Author"
.PP 
Generated automatically by Doxygen for LMDB from the source code\&.