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GNU Info (gdbm.info)IntroIntroduction to GNU `dbm'. ************************** GNU `dbm' (`gdbm')is a library of database functions that use extendible hashing and works similar to the standard UNIX `dbm' functions. These routines are provided to a programmer needing to create and manipulate a hashed database. (`gdbm' is _NOT_ a complete database package for an end user.) The basic use of `gdbm' is to store key/data pairs in a data file. Each key must be unique and each key is paired with only one data item. The keys can not be directly accessed in sorted order. The basic unit of data in `gdbm' is the structure: typedef struct { char *dptr; int dsize; } datum; This structure allows for arbitrary sized keys and data items. The key/data pairs are stored in a `gdbm' disk file, called a `gdbm' database. An application must open a `gdbm' database to be able manipulate the keys and data contained in the database. `gdbm' allows an application to have multiple databases open at the same time. When an application opens a `gdbm' database, it is designated as a `reader' or a `writer'. A `gdbm' database opened by at most one writer at a time. However, many readers may open the database open simultaneously. Readers and writers can not open the `gdbm' database at the same time. automatically generated by info2www version 1.2.2.9 |