CDBW(3)

CDBW(3) | Library Functions Manual | CDBW(3)

# NAME

`cdbw_open`, `cdbw_put`, `cdbw_put_data`, `cdbw_put_key`, `cdbw_stable_seeder`, `cdbw_output`, `cdbw_close` — create constant databases

# SYNOPSIS

`#include <cdbw.h>`

struct cdbw *
`cdbw_open`(void);

int
`cdbw_put`(struct cdbw *cdbw, const void *key, size_t keylen, const void *data, size_t datalen);

int
`cdbw_put_data`(struct cdbw *cdbw, const void *data, size_t datalen, uint32_t *index);

int
`cdbw_put_key`(struct cdbw *cdbw, const void *key, size_t keylen, uint32_t index);

uint32_t
`cdbw_stable_seeder`(void);

int
`cdbw_output`(struct cdbw *cdbw, int output, const char *descr, uint32_t (*seedgen)(void));

void
`cdbw_close`(struct cdbw *cdbw);

# DESCRIPTION

The `cdbw` functions are used to create a constant databases for use with cdbr(3). Details about the file format, including overhead and limitations, can be found in cdb(5).

`cdbw_open`() prepares a new `cdb` writer. The function returns a handle to pass to the other functions.

`cdbw_close`() frees all resources associated with the handle.

`cdbw_put`() adds the given (key,value) pair after checking for a duplicate key. `cdbw_put_data`() adds the given value to the writer without adding a key reference. The returned index can be used in subsequent calls to `cdbw_put_key`() to add one or more keys pointing to this value. `cdbw_put_key`() checks for duplicate keys and valid index arguments. On success it adds the given key.

`cdbw_output`() computes the database file and writes it to the given descriptor. The function returns an error if the file cannot be written correctly. The descr parameter, a string of up to 16 bytes, provides a human readable description of the database content. The seedgen parameter can be used to override the default PRNG. The bitwise layout of the output depends on the chosen seed. The function should return a different value for each invocation. The `cdbw_stable_seeder`() can be used to create reproducible output. It may be slower than the default.

# SEE ALSO

cdbr(3), cdb(5)

# HISTORY

Support for the `cdb` format first appeared in NetBSD 6.0.

# AUTHORS

The `cdbr` and `cdbw` functions have been written by Joerg Sonnenberger <joerg@NetBSD.org>.

February 6, 2014 | NetBSD 11.0