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dbm(3)
NAME
  dbminit, fetch, store, delete, firstkey, nextkey, forder - Database
  subroutines

SYNOPSIS
  #include <dbm.h>

  typedef struct {
      char *dptr
	  int dzise

  } datum;

  int dbminit(
	  char *file );

  int store(
	  datum key,
	  datum content );

  int delete(
	  datum key );

  datum firstkey(
	  void );

  datum nextkey(
	  datum key );

  long forder(
	  datum key );

LIBRARY
  DBM Library (libdbm.a)

PARAMETERS
  file
      Specifies the database file.

  key Specifies the key.

  content
      Specifies a value associated with the key parameter.

DESCRIPTION
  The dbminit(), fetch(), store(), delete(), firstkey(), nextkey(), and
  forder() functions maintain key/content pairs in a database. They are
  obtained with the -ldbm loader option. The dbm library is provided only for
  backwards compatibility, having been obsoleted by the ndbm functions in
  libc. See the manual page for ndbm for more information.

  The dbminit(), fetch(), store(), delete(), firstkey(), nextkey(), and
  forder() functions handle very large databases (up to a billion blocks) and
  access a keyed item in one or two file system accesses. Arbitrary binary
  data, as well as normal ASCII strings, are allowed.

  The database is stored in two files. One file is a directory containing a
  bit map and has .dir as its suffix. The second file contains all data and
  has .pag as its suffix.

  Before a database can be accessed, it must be opened by the dbminit()
  function. At the time that dbminit() is called, the file.dir and file.pag
  files must exist. (An empty database is created by creating zero-length
  .dir and .pag files.)

  Once open, the data stored under a key is accessed by the fetch() function
  and data is placed under a key by the store() function. A key (and its
  associated contents) is deleted by the delete() function. A linear pass
  through all keys in a database may be made by use of the firstkey() and
  nextkey() functions. The firstkey() function returns the first key in the
  database. With any key, the nextkey() function returns the next key in the
  database. The following code traverses the database:

       for (key = firstkey(); key.dptr != NULL; key = nextkey(key))

RETURN VALUES
  Upon successful completion, the functions that return an int return 0
  (zero). Otherwise, a negative number is returned. The functions that return
  a datum indicate errors with a null (0) dptr.

SEE ALSO
  Functions: ndbm(3)

Index for Section 3

Alphabetical listing for D

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