File: gdbm.info, Node: Top, Next: Copying, Up: (dir) The GNU database manager. ************************* GNU `dbm' is a library of functions implementing a hashed database on a disk file. This manual documents GNU `dbm' Version 1.10 (`gdbm'). The software was originally written by Philip A. Nelson. This document was originally written by Pierre Gaumond from texts written by Phil. * Menu: Introduction: * Copying:: Your rights. * Intro:: Introduction to GNU dbm. * List:: List of functions. Functions: * Open:: Opening the database. * Close:: Closing the database. * Store:: Inserting and replacing records in the database. * Fetch:: Searching records in the database. * Delete:: Removing records from the database. * Sequential:: Sequential access to records. * Reorganization:: Database reorganization. * Sync:: Insure all writes to disk have competed. * Flat files:: Export and import to Flat file format. * Errors:: Convert internal error codes into English. * Options:: Setting internal options. * Locking:: File locking. Programs * testgdbm:: Test and modify a GDBM database. * gdbmexport:: Export a database into a portable format. Other topics: * Error codes:: Error codes returned by `gdbm' calls. * Variables:: Two useful variables. * Compatibility:: Compatibility with UNIX dbm and ndbm. * Bugs:: Problems and bugs. * Resources:: Additional resources, * GNU Free Documentation License:: Document license. * Index:: Index File: gdbm.info, Node: Copying, Next: Intro, Prev: Top, Up: Top 1 Copying Conditions. ********************* This library is "free"; this means that everyone is free to use it and free to redistribute it on a free basis. GNU `dbm' (`gdbm') is not in the public domain; it is copyrighted and there are restrictions on its distribution, but these restrictions are designed to permit everything that a good cooperating citizen would want to do. What is not allowed is to try to prevent others from further sharing any version of `gdbm' that they might get from you. Specifically, we want to make sure that you have the right to give away copies `gdbm', that you receive source code or else can get it if you want it, that you can change these functions or use pieces of them in new free programs, and that you know you can do these things. To make sure that everyone has such rights, we have to forbid you to deprive anyone else of these rights. For example, if you distribute copies `gdbm', you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must tell them their rights. Also, for our own protection, we must make certain that everyone finds out that there is no warranty for anything in the `gdbm' distribution. If these functions are modified by someone else and passed on, we want their recipients to know that what they have is not what we distributed, so that any problems introduced by others will not reflect on our reputation. `Gdbm' is currently distributed under the terms of the GNU General Public License, Version 3. (_NOT_ under the GNU General Library Public License.) A copy the GNU General Public License is included with the distribution of `gdbm'. File: gdbm.info, Node: Intro, Next: List, Prev: Copying, Up: Top 2 Introduction to GNU `dbm'. **************************** GNU `dbm' (`gdbm') is a library of database functions that use extensible 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 can be opened by at most one writer at a time. However, many readers may open the database simultaneously. Readers and writers can not open the `gdbm' database at the same time. File: gdbm.info, Node: List, Next: Open, Prev: Intro, Up: Top 3 List of functions. ******************** The following is a quick list of the functions contained in the `gdbm' library. The include file `gdbm.h', that can be included by the user, contains a definition of these functions. #include <gdbm.h> GDBM_FILE gdbm_open(name, block_size, flags, mode, fatal_func); void gdbm_close(dbf); int gdbm_store(dbf, key, content, flag); datum gdbm_fetch(dbf, key); int gdbm_delete(dbf, key); datum gdbm_firstkey(dbf); datum gdbm_nextkey(dbf, key); int gdbm_reorganize(dbf); void gdbm_sync(dbf); int gdbm_exists(dbf, key); char *gdbm_strerror(errno); int gdbm_setopt(dbf, option, value, size); int gdbm_fdesc(dbf); The `gdbm.h' include file is often in the `/usr/local/include' directory. (The actual location of `gdbm.h' depends on your local installation of `gdbm'.) File: gdbm.info, Node: Open, Next: Close, Prev: List, Up: Top 4 Opening the database. *********************** -- gdbm interface: GDBM_FILE gdbm_open (const char *NAME, int BLOCK_SIZE, int FLAGS, int MODE, void (*fatal_func)(const char *)) Initializes `gdbm' system. If the file has a size of zero bytes, a file initialization procedure is performed, setting up the initial structure in the file. The arguments are: NAME The name of the file (the complete name, `gdbm' does not append any characters to this name). BLOCK_SIZE It is used during initialization to determine the size of various constructs. It is the size of a single transfer from disk to memory. This parameter is ignored if the file has been previously initialized. The minimum size is 512. If the value is less than 512, the file system block size is used, otherwise the value of BLOCK_SIZE is used. FLAGS If `flags' is set to `GDBM_READER', the user wants to just read the database and any call to `gdbm_store' or `gdbm_delete' will fail. Many readers can access the database at the same time. If `flags' is set to `GDBM_WRITER', the user wants both read and write access to the database and requires exclusive access. If `flags' is set to `GDBM_WRCREAT', the user wants both read and write access to the database and wants it created if it does not already exist. If `flags' is set to `GDBM_NEWDB', the user want a new database created, regardless of whether one existed, and wants read and write access to the new database. The following may also be logically or'd into the database flags: `GDBM_SYNC', which causes all database operations to be synchronized to the disk, `GDBM_NOLOCK', which prevents the library from performing any locking on the database file, and `GDBM_NOMMAP', which disables the memory mapping mechanism. The option `GDBM_FAST' is now obsolete, since `gdbm' defaults to no-sync mode. If the host `open' call (*note open: (open(2))open.) supports the `O_CLOEXEC' flag, the `GDBM_CLOEXEC' can be or'd into the flags, to enable the close-on-exec flag for the database file descriptor. MODE File mode (see *note change permissions of a file: (chmod(2))chmod, and *note open a file: (open(2))open.), which is used if the file is created). FATAL_FUNC A function for `gdbm' to call if it detects a fatal error. The only parameter of this function is a string. If the value of `NULL' is provided, `gdbm' will use a default function. The return value, is the pointer needed by all other functions to access that `gdbm' file. If the return is the `NULL' pointer, `gdbm_open' was not successful. The errors can be found in `gdbm_errno' variable (*note gdbm_errno: Variables.). Available error codes are discussed in *note Error codes::. In all of the following calls, the parameter DBF refers to the pointer returned from `gdbm_open'. File: gdbm.info, Node: Close, Next: Store, Prev: Open, Up: Top 5 Closing the database. *********************** It is important that every file opened is also closed. This is needed to update the reader/writer count on the file: -- gdbm interface: void gdbm_close (GDBM_FILE DBF) This function closes the `gdbm' file and frees all memory associated with it. The parameter is: DBF The pointer returned by `gdbm_open'. File: gdbm.info, Node: Store, Next: Fetch, Prev: Close, Up: Top 6 Inserting and replacing records in the database. ************************************************** -- gdbm interface: int gdbm_store (GDBM_FILE DBF, datum KEY, datum CONTENT, int FLAG) The function `gdbm_store' inserts or replaces records in the database. The parameters are: DBF The pointer returned by `gdbm_open'. KEY The search key. CONTENT The data to be associated with the key. FLAG Defines the action to take when the key is already in the database. The value `GDBM_REPLACE' (defined in `gdbm.h') asks that the old data be replaced by the new CONTENT. The value `GDBM_INSERT' asks that an error be returned and no action taken if the KEY already exists. This function can return the following values: -1 The item was not stored in the database because the caller was not an official writer or either KEY or CONTENT have a `NULL' `dptr' field. Both KEY and CONTENT must have the `dptr' field be a non-`NULL' value. Since a `NULL' `dptr' field is used by other functions to indicate an error, it cannot be valid data. +1 The item was not stored because the argument FLAG was `GDBM_INSERT' and the KEY was already in the database. 0 No error. The value of CONTENT is keyed by KEY. The file on disk is updated to reflect the structure of the new database before returning from this function. If you store data for a KEY that is already in the data base, `gdbm' replaces the old data with the new data if called with `GDBM_REPLACE'. You do not get two data items for the same `key' and you do not get an error from `gdbm_store'. The size in `gdbm' is not restricted like `dbm' or `ndbm'. Your data can be as large as you want. File: gdbm.info, Node: Fetch, Next: Delete, Prev: Store, Up: Top 7 Searching for records in the database. **************************************** -- gdbm interface: datum gdbm_fetch (GDBM_FILE DBF, datum KEY) Looks up a given KEY and returns the information associated with it. The `dptr' field in the structure that is returned points to a memory block allocated by `malloc'. It is the caller's responsibility to free it when no longer needed. If the `dptr' is `NULL', no data was found. The parameters are: DBF The pointer returned by `gdbm_open'. KEY The search key. An example of using this function: content = gdbm_fetch (dbf, key); if (content.dptr == NULL) { fprintf(stderr, "key not found\n"); } else { /* do something with content.dptr */ } You may also search for a particular key without retrieving it: -- gdbm interface: int gdbm_exists (GDBM_FILE DBF, datum KEY) Returns `true' (`1') if the KEY exists in DBF and `false' (`0') otherwise. The parameters are: DBF The pointer returned by `gdbm_open'. KEY The search key. File: gdbm.info, Node: Delete, Next: Sequential, Prev: Fetch, Up: Top 8 Removing records from the database. ************************************* To remove some data from the database, use the `gdbm_delete' function. -- gdbm interface: int gdbm_delete (GDBM_FILE DBF, datum KEY) Deletes the data associated with the given KEY, if it exists in the database DBF. The file on disk is updated to reflect the structure of the new database before returning from this function. The parameters are: DBF The pointer returned by `gdbm_open'. DATUM KEY The search key. The function returns `-1' if the item is not present or the requester is a reader. The return of `0' marks a successful delete. File: gdbm.info, Node: Sequential, Next: Reorganization, Prev: Delete, Up: Top 9 Sequential access to records. ******************************* The next two functions allow for accessing all items in the database. This access is not `key' sequential, but it is guaranteed to visit every `key' in the database once. The order has to do with the hash values. `gdbm_firstkey' starts the visit of all keys in the database. `gdbm_nextkey' finds and reads the next entry in the hash structure for `dbf'. -- gdbm interface: datum gdbm_firstkey (GDBM_FILE DBF) Initiate sequential access to the database DBF. The returned value is the first key accessed in the database. If the `dptr' field in the returned datum is `NULL', the database contains no data. Otherwise, `dptr' points to a memory block obtained from `malloc', which holds the key value. The caller is responsible for freeing this memory block when no longer needed. -- gdbm interface: datum gdbm_nextkey (GDBM_FILE DBF, datum PREV) This function continues the iteration over the keys in DBF, initiated by `gdbm_firstkey'. The parameter PREV holds the value returned from a previous call to `gdbm_nextkey' or `gdbm_firstkey'. The function returns next key from the database. If the `dptr' field in the returned datum is `NULL', all keys in the database has been visited. Otherwise, `dptr' points to a memory block obtained from `malloc', which holds the key value. The caller is responsible for freeing this memory block when no longer needed. These functions were intended to visit the database in read-only algorithms, for instance, to validate the database or similar operations. The usual algorithm for sequential access is: key = gdbm_firstkey (dbf); while (key.dptr) { datum nextkey; /* do something with the key */ ... /* Obtain the next key */ nextkey = gdbm_nextkey (dbf, key); /* Reclaim the memory used by the key */ free (key.dptr); /* Use nextkey in the next iteration. */ key = nextkey; } Care should be taken when the `gdbm_delete' function is used in such a loop. File visiting is based on a "hash table". The `gdbm_delete' function re-arranges the hash table to make sure that any collisions in the table do not leave some item "un-findable". The original key order is _not_ guaranteed to remain unchanged in all instances. So it is possible that some key will not be visited if a loop like the following is executed: key = gdbm_firstkey (dbf); while (key.dptr) { datum nextkey; if (some condition) { gdbm_delete (dbf, key); } nextkey = gdbm_nextkey (dbf, key); free (key.dptr); key = nextkey; } File: gdbm.info, Node: Reorganization, Next: Sync, Prev: Sequential, Up: Top 10 Database reorganization. *************************** The following function should be used very seldom. -- gdbm interface: int gdbm_reorganize (GDBM_FILE DBF) Reorganizes the database. The parameter is: DBF The pointer returned by `gdbm_open'. If you have had a lot of deletions and would like to shrink the space used by the `gdbm' file, this function will reorganize the database. This results, in particular, in shortening the length of a `gdbm' file by removing the space occupied by deleted records. This reorganization requires creating a new file and inserting all the elements in the old file DBF into the new file. The new file is then renamed to the same name as the old file and DBF is updated to contain all the correct information about the new file. If an error is detected, the return value is negative. The value zero is returned after a successful reorganization. File: gdbm.info, Node: Sync, Next: Flat files, Prev: Reorganization, Up: Top 11 Database Synchronization *************************** Unless your database was opened with the `GDBM_SYNC' flag, `gdbm' does not wait for writes to be flushed to the disk before continuing. This allows for faster writing of databases at the risk of having a corrupted database if the application terminates in an abnormal fashion. The following function allows the programmer to make sure the disk version of the database has been completely updated with all changes to the current time. -- gdbm interface: void gdbm_sync (GDBM_FILE DBF) Synchronizes the changes in DBF with its disk file. The parameter is a pointer returned by `gdbm_open'. This function would usually be called after a complete set of changes have been made to the database and before some long waiting time. The `gdbm_close' function automatically calls the equivalent of `gdbm_sync' so no call is needed if the database is to be closed immediately after the set of changes have been made. File: gdbm.info, Node: Flat files, Next: Errors, Prev: Sync, Up: Top 12 Export and Import ******************** `Gdbm' databases can be converted into a portable "flat format". This format can be used, for example, to migrate between the different versions of `gdbm' databases. Generally speaking, flat files are safe to send over the network, and can be used to recreate the database on another machine. The recreated database is guaranteed to be a byte-to-byte equivalent of the database from which the flat file was created. This does not necessarily mean, however, that this file can be used in the same way as the original one. For example, if the original database contained non-ASCII data (e.g. C structures, integers etc.), the recreated database can be of any use only if the target machine has the same integer size and byte ordering as the source one and if its C compiler uses the same packing conventions as the one which generated C which populated the original database. In general, such binary databases are not portable between machines, unless you follow some stringent rules on what data is written to them and how it is interpreted. -- gdbm interface: int gdbm_export (GDBM_FILE DBF, const char *EXPORTFILE, int FLAG, int MODE) Create a flat file from the `gdbm' database. The parameters are: DBF A pointer to the source database, returned by a call to `gdbm_open'. The database must be open in `GDBM_WRITER' mode. EXPORTFILE The name of the output file. FLAG How to create the output file. If FLAG is `GDBM_WRCREAT', the file will be created if it does not exist already. Otherwise, if it is `GDBM_NEWDB', it will be created if it does not exist, and truncated otherwise. MODE The permissions to use when creating the output file. See *note open a file: (open(2))open, for a detailed discussion. -- gdbm interface: int gdbm_import (GDBM_FILE DBF, const char *IMPORTFILE, int FLAG) Populates the database from an existing flat file. DBF A pointer to the source database, returned by a call to `gdbm_open'. The database must be open in `GDBM_WRITER' mode. IMPORTFILE The name of the input flat file. The file must exist. FLAG The FLAG argument to be passed to `gdbm_store' function when adding new records. *Note Store::, for a description of its effect. See also *note gdbmexport::, *note testgdbm export::, and *note testgdbm import::. File: gdbm.info, Node: Errors, Next: Options, Prev: Flat files, Up: Top 13 Error strings. ***************** To convert a `gdbm' error code into English text, use this routine: -- gdbm interface: const char * gdbm_strerror (gdbm_error ERRNO) Converts ERRNO (which is an integer value) into a human-readable descriptive text. Returns a pointer to a static string. The caller must not alter or free the returned pointer. The ERRNO argument is usually the value of the global variable `gdbm_errno'. *Note gdbm_errno: Variables. File: gdbm.info, Node: Options, Next: Locking, Prev: Errors, Up: Top 14 Setting options ****************** `Gdbm' supports the ability to set certain options on an already open database. -- gdbm interface: int gdbm_setopt (GDBM_FILE DBF, int OPTION, void *VALUE, int SIZE) Sets an option on the database or returns the value of an option. The parameters are: DBF The pointer returned by `gdbm_open'. OPTION The option to be set or retreived. VALUE A pointer to the value to which OPTION will be set or where to place the option value (depending on the option). SIZE The length of the data pointed to by VALUE. The valid options are: GDBM_SETCACHESIZE GDBM_CACHESIZE Set the size of the internal bucket cache. This option may only be set once on each GDBM_FILE descriptor, and is set automatically to 100 upon the first access to the database. The VALUE should point to a `size_t' holding the desired cache size. The `GDBM_CACHESIZE' option is provided for compatibility with earlier versions. GDBM_GETCACHESIZE Return the size of the internal bucket cache. The VALUE should point to a `size_t' variable, where the size will be stored. GDBM_GETFLAGS Return the flags describing the state of the database. The VALUE should point to a `int' variable where to store the flags. The return is the same as the flags used when opening the database (*note gdbm_open: Open.), except that it reflects the current state (which may have been altered by another calls to `gdbm_setopt'. GDBM_FASTMODE Enable or disable the "fast writes mode", i.e. writes without subsequent synchronization. The VALUE should point to an integer: `TRUE' to enable fast mode, and `FALSE' to disable it. This option is retained for compatibility with previous versions of `gdbm'. Its effect is the reverse of `GDBM_SETSYNCMODE' (see below). GDBM_SETSYNCMODE GDBM_SYNCMODE Turn on or off file system synchronization operations. This setting defaults to off. The VALUE should point to an integer: `TRUE' to turn synchronization on, and `FALSE' to turn it off. Note, that this option is a reverse of `GDBM_FASTMODE', i.e. calling `GDBM_SETSYNCMODE' with `TRUE' has the same effect as calling `GDBM_FASTMODE' with `FALSE'. The `GDBM_SYNCMODE' option is provided for compatibility with earlier versions. GDBM_GETSYNCMODE Return the current synchronization status. The VALUE should point to an `int' where the status will be stored. GDBM_SETCENTFREE GDBM_CENTFREE _NOTICE: This feature is still under study._ Set central free block pool to either on or off. The default is off, which is how previous versions of `gdbm' handled free blocks. If set, this option causes all subsequent free blocks to be placed in the _global_ pool, allowing (in theory) more file space to be reused more quickly. The VALUE should point to an integer: `TRUE' to turn central block pool on, and `FALSE' to turn it off. The `GDBM_CENTFREE' option is provided for compatibility with earlier versions. GDBM_SETCOALESCEBLKS GDBM_COALESCEBLKS _NOTICE: This feature is still under study._ Set free block merging to either on or off. The default is off, which is how previous versions of `gdbm' handled free blocks. If set, this option causes adjacent free blocks to be merged. This can become a CPU expensive process with time, though, especially if used in conjunction with GDBM_CENTFREE. The VALUE should point to an integer: `TRUE' to turn free block merging on, and `FALSE' to turn it off. GDBM_GETCOALESCEBLKS Return the current status of free block merging. The VALUE should point to an `int' where the status will be stored. GDBM_SETMAXMAPSIZE Sets maximum size of a memory mapped region. The VALUE should point to a value of type `size_t', `unsigned long' or `unsigned'. The actual value is rounded to the nearest page boundary (the page size is obtained from `sysconf(_SC_PAGESIZE)'). GDBM_GETMAXMAPSIZE Return the maximum size of a memory mapped region. The VALUE should point to a value of type `size_t' where to return the data. GDBM_SETMMAP Enable or disable memory mapping mode. The VALUE should point to an integer: `TRUE' to enable memory mapping or `FALSE' to disable it. GDBM_GETMMAP Check whether memory mapping is enabled. The VALUE should point to an integer where to return the status. GDBM_GETDBNAME Return the name of the database disk file. The VALUE should point to a variable of type `char**'. A pointer to the newly allocated copy of the file name will be placed there. The caller is responsible for freeing this memory when no longer needed. For example: char *name; if (gdbm_setopt (dbf, GDBM_GETDBNAME, &name, sizeof (name))) { fprintf (stderr, "gdbm_setopt failed: %s\n", gdbm_strerror (gdbm_errno)); } else { printf ("database name: %s\n", name); free (name); } The return value will be `-1' upon failure, or `0' upon success. The global variable `gdbm_errno' will be set upon failure. For instance, to set a database to use a cache of 10, after opening it with `gdbm_open', but prior to accessing it in any way, the following code could be used: int value = 10; ret = gdbm_setopt (dbf, GDBM_CACHESIZE, &value, sizeof (int)); File: gdbm.info, Node: Locking, Next: testgdbm, Prev: Options, Up: Top 15 File Locking. **************** With locking disabled (if `gdbm_open' was called with `GDBM_NOLOCK'), the user may want to perform their own file locking on the database file in order to prevent multiple writers operating on the same file simultaneously. In order to support this, the `gdbm_fdesc' routine is provided. -- gdbm interface: int gdbm_fdesc (GDBM_FILE DBF) Returns the file descriptor of the database DBF. This value can be used as an argument to `flock', `lockf' or similar calls. File: gdbm.info, Node: testgdbm, Next: gdbmexport, Prev: Locking, Up: Top 16 Test and modify a GDBM database. *********************************** The `testgdbm' utility allows you to view and modify an existing GDBM database or to create a new one. When invoked without options, it tries to open a database file called `junk.gdbm', located in the current working directory. You can change this default using the `-g' command line option. This option takes a single argument, specifying the file name to open, e.g.: $ testgdbm -g file.db The database will be opened in read-write mode, unless the `-r' option is specified, in which case it will be opened only for reading. If the database does not exist, `testgdbm' will create it. There is a special option `-n', which instructs the utility to create a new database. If it is used and if the database already exists, it will be deleted, so use it sparingly. * Menu: * invocation:: * shell:: File: gdbm.info, Node: invocation, Next: shell, Up: testgdbm 16.1 testgdbm invocation ======================== The following table summarizes all `testgdbm' command line options: `-b SIZE' Set block size. `-c SIZE' Set cache size. `-g FILE' Operate on FILE instead of the default `junk.gdbm'. `-h' Print a concise help summary. `-n' Create the database. `-r' Open the database in read-only mode. `-s' Synchronize to the disk after each write. `-v' Print program version and licensing information and exit. File: gdbm.info, Node: shell, Prev: invocation, Up: testgdbm 16.2 testgdbm interactive mode ============================== After successful startup, `testgdbm' starts a loop, in which it reads commands from the user, executes them and prints the results on the standard output. If the standard input is attached to a console, `testgdbm' runs in interactive mode, which is indicated by its "prompt": testgdbm> _ The utility finishes when it reads the `quit' command (see below) or detects end-of-file on its standard input, whichever occurs first. A `testgdbm' command consists of a "command verb", optionally followed by one or two "arguments", separated by any amount of white space. A command verb can be entered either in full or in an abbreviated form, as long as that abbreviation does not match any other verb. For example, `co' can be used instead of `count' and `ca' instead of `cache'. Furthermore, many command verbs also have single-letter forms, called "command letters". An argument is any sequence of non-whitespace characters. Notice, that currently there is no way to enter arguments containing white space. This limitation will be removed in future releases. Each command takes at most two "formal parameters", which can be optional or mandatory. If the number of actual arguments is less than the number of mandatory parameters, `testgdbm' will prompt you to supply missing arguments. For example, the `store' command takes two mandatory parameters, so if you invoked it with no arguments, you would be prompted twice to supply the necessary data, as shown in example below: testgdbm> store key> three data> 3 However, such prompting is possible only in interactive mode. In non-interactive mode (e.g. when running a script), all arguments must be supplied with each command, otherwise `testgdbm' will report an error and exit immediately. Some commands produce excessive amounts of output. To help you follow it, `testgdbm' uses a pager utility to display such output. The name of the pager utility is taken from the environment variable `PAGER'. The pager is invoked only in interactive mode and only if the estimated number of output lines is greater then the number of lines on your screen. Many of the `testgdbm' commands operate on database key and data values. The utility assumes that both keys and data are ASCII strings, either nul-terminated or not. By default, it is assumed that strings are nul-terminated. You can change this by using `z' (`key-zero', for keys) and `Z' (`data-zero', for data) commands. The following table summarizes all available commands: -- command verb: count -- command abbrev: co -- command letter: c Print the number of entries in the database. -- command verb: delete KEY -- command abbrev: de KEY -- command letter: d KEY Delete entry with a given KEY -- command verb: export FILE-NAME [truncate] -- command abbrev: e FILE-NAME [truncate] Export the database to the flat file FILE-NAME. *Note Flat files::, for a description of the flat file format and its purposes. This command will not overwrite an existing file, unless the word `truncate' is given as its second argument. See also *note gdbmexport::. -- command verb: fetch KEY -- command abbrev: fe KEY -- command letter: f KEY Fetch and display a record with the given KEY. -- command verb: import FILE-NAME [replace] -- command abbrev: i FILE-NAME [replace] Import data from a flat dump file FILE-NAME (*note Flat files::). If the word `replace' is given as the second argument, any records with the same keys as the already existing ones will replace them. -- command verb: list -- command abbrev: l List the contents of the database (*note pager::). -- command verb: next [KEY] -- command abbrev: n [KEY] Sequential access: fetch and display a next record. If KEY is given, a record following one with this key will be fetched. Otherwise, the key supplied by the latest `1', `2' or N command will be used. See also `first', below. *Note Sequential::, for more information on sequential access. -- command verb: quit -- command abbrev: q Close the database and quit the utility. -- command verb: store KEY DATA -- command abbrev: sto KEY DATA -- command letter: s KEY DATA Store the DATA with KEY in the database. If KEY already exists, its data will be replaced. -- command verb: first -- command abbrev: fi -- command letter: 1 Fetch and display the first record in the database. Subsequent records can be fetched using `next' command (see above). *Note Sequential::, for more information on sequential access. -- command verb: read FILE [replace] -- command abbrev: rea FILE [replace] -- command letter: < FILE [replace] Read entries from FILE and store them in the database. If the word `replace' is given as the second argument, any existing records with matching keys will be replaced. -- command verb: reorganize -- command abbrev: reo -- command letter: r Reorganize the database (*note Reorganization::). -- command verb: key-zero -- command abbrev: k -- command letter: z Toggle key nul-termination. Use `status' to inspect the current state. *Note nul-termination::. -- command verb: avail -- command abbrev: a -- command letter: A Print the "avail list". -- command verb: bucket -- command abbrev: b -- command letter: B Print the bucket number NUM. -- command verb: current -- command abbrev: cu -- command letter: C Print the current bucket. -- command verb: dir -- command abbrev: di -- command letter: D Print hash directory. -- command verb: header -- command abbrev: hea -- command letter: F Print file header. -- command verb: hash KEY -- command abbrev: ha KEY -- command letter: H KEY Compute and display the hash value for the given KEY. -- command verb: cache -- command abbrev: ca -- command letter: K Print the bucket cache. -- command verb: status -- command abbrev: sta -- command letter: S Print current program status. The following example shows the information displayed: Database file: junk.gdbm Zero terminated keys: yes Zero terminated data: yes -- command verb: version -- command abbrev: v Print the version of `gdbm'. -- command verb: data-zero -- command abbrev: da -- command letter: Z Toggle data nul-termination. Use `status' to examine the current status. *Note nul-termination::. -- command verb: help -- command abbrev: hel -- command letter: ? Print a concise command summary, showing each command letter and verb with its parameters and a short description of what it does. Optional arguments are enclosed in square brackets. File: gdbm.info, Node: gdbmexport, Next: Error codes, Prev: testgdbm, Up: Top 17 Export a database into a portable format. ******************************************** The `gdbmexport' utility converts the database into a portable "flat format". Files in this format can be used to populate databases using the `gdbm_import' function (*note gdbm_import: Flat files.) or the `i' command of `testgdbm' utility (*note testgdbm import::). In many cases files in this format are suitable for sending over the network to populate the database on another machine. The only exception to this are databases whose records contain non-ASCII data (e.g. C structures, integers etc.). For such databases you will be better off by writing a specialized utility to convert them to an architecture-independent format. If `gdbmexport' is linked with `libgdbm' version 1.8.3, it can be used to convert databases from old to new format. The utility takes two mandatory arguments: the name of the database file to convert and the output file name, e.g.: $ gdbmexport junk.gdbm junk.flat In addition two options are understood: `-h' Display short usage summary and exit. `-v' Display program version and licensing information, and exit. File: gdbm.info, Node: Error codes, Next: Variables, Prev: gdbmexport, Up: Top 19 Error codes ************** This chapter summarizes the error codes which can be set by the functions in `gdbm' library. GDBM_NO_ERROR No error occurred. GDBM_MALLOC_ERROR Memory allocation failed. Not enough memory. GDBM_BLOCK_SIZE_ERROR This error is set by the `gdbm_open' function (*note Open::), if the value of its BLOCK_SIZE argument is incorrect. GDBM_FILE_OPEN_ERROR The library was not able to open a disk file. This can be set by `gdbm_open' (*note Open::), `gdbm_export' and `gdbm_import' functions (*note Flat files::). Inspect the value of the system `errno' variable to get more detailed diagnostics. GDBM_FILE_WRITE_ERROR Writing to a disk file failed. This can be set by `gdbm_open' (*note Open::), `gdbm_export' and `gdbm_import' functions. Inspect the value of the system `errno' variable to get more detailed diagnostics. GDBM_FILE_SEEK_ERROR Positioning in a disk file failed. This can be set by `gdbm_open' (*note Open::) function. Inspect the value of the system `errno' variable to get a more detailed diagnostics. GDBM_FILE_READ_ERROR Reading from a disk file failed. This can be set by `gdbm_open' (*note Open::), `gdbm_export' and `gdbm_import' functions. Inspect the value of the system `errno' variable to get a more detailed diagnostics. GDBM_BAD_MAGIC_NUMBER The file given as argument to `gdbm_open' function is not a valid `gdbm' file: it has a wrong magic number. GDBM_EMPTY_DATABASE The file given as argument to `gdbm_open' function is not a valid `gdbm' file: it has zero length. GDBM_CANT_BE_READER This error code is set by the `gdbm_open' function if it is not able to lock file when called in `GDBM_READER' mode (*note GDBM_READER: Open.). GDBM_CANT_BE_WRITER This error code is set by the `gdbm_open' function if it is not able to lock file when called in writer mode (*note Open::). GDBM_READER_CANT_DELETE Set by the `gdbm_delete' (*note Delete::) if it attempted to operate on a database that is open in read-only mode (*note GDBM_READER: Open.). GDBM_READER_CANT_STORE Set by the `gdbm_store' (*note Store::) if it attempted to operate on a database that is open in read-only mode (*note GDBM_READER: Open.). GDBM_READER_CANT_REORGANIZE Set by the `gdbm_reorganize' (*note Reorganization::) if it attempted to operate on a database that is open in read-only mode (*note GDBM_READER: Open.). GDBM_UNKNOWN_UPDATE Currently unused. Reserved for future uses. GDBM_ITEM_NOT_FOUND Requested item was not found. This error is set by `gdbm_delete' (*note Delete::) and `gdbm_fetch' (*note Fetch::) when the requested KEY value is not found in the database. GDBM_REORGANIZE_FAILED The `gdbm_reorganize' function is not able to create a temporary database. *Note Reorganization::. GDBM_CANNOT_REPLACE Cannot replace existing item. This error is set by the `gdbm_store' if the requested KEY value is found in the database and the FLAG parameter is not `GDBM_REPLACE'. *Note Store::, for a detailed discussion. GDBM_ILLEGAL_DATA Either KEY or CONTENT parameter was wrong in a call to to `gdbm_store' (*note Store::). GDBM_OPT_ALREADY_SET Requested option can be set only once and was already set. This error is returned by the `gdbm_setopt' function. *Note GDBM_CACHESIZE: Options. GDBM_OPT_ILLEGAL The OPTION argument is not valid or the VALUE argument points to an invalid value in a call to `gdbm_setopt' function. *Note Options::. GDBM_BYTE_SWAPPED The `gdbm_open' function (*note Open::) attempts to open a database which is created on a machine with different byte ordering. GDBM_BAD_FILE_OFFSET The `gdbm_open' function (*note Open::) sets this error code if the file it tries to open has a wrong magic number. GDBM_BAD_OPEN_FLAGS Set by the `gdbm_export' function if supplied an invalid FLAGS argument. *Note Flat files::. GDBM_FILE_STAT_ERROR Getting information about a disk file failed. The system `errno' will give more details about the error. This error can be set by the following functions: `gdbm_open', `gdbm_reorganize'. GDBM_FILE_EOF End of file was encountered where more data was expected to be present. This error can occur when fetching data from the database and usually means that the database is truncated or otherwise corrupted. This error can be set by any GDBM function that does I/O. Some of these functions are: `gdbm_delete', `gdbm_exists', `gdbm_fetch', `gdbm_export', `gdbm_import', `gdbm_reorganize', `gdbm_firstkey', `gdbm_nextkey', `gdbm_store'. File: gdbm.info, Node: Variables, Next: Compatibility, Prev: Error codes, Up: Top 18 Useful global variables. *************************** The following global variables and constants are available: -- Variable: gdbm_error gdbm_errno This variable contains error code from the last failed `gdbm' call. *Note Error codes::, for a list of available error codes and their descriptions. Use `gdbm_strerror' (*note Errors::) to convert it to a descriptive text. -- Variable: const char * gdbm_errlist[] This variable is an array of error descriptions, which is used by `gdbm_strerror' to convert error codes to human-readable text (*note Errors::). You can access it directly, if you wish so. It contains `_GDBM_MAX_ERRNO + 1' elements and can be directly indexed by the error code to obtain a corresponding descriptive text. -- Constant: _GDBM_MIN_ERRNO The minimum error code used by `gdbm'. -- Constant: _GDBM_MAX_ERRNO The maximum error code used by `gdbm'. -- Variable: const char * gdbm_version A string containing the version information. -- Variable: int const gdbm_version_number[3] This variable contains the `gdbm' version numbers: Index Meaning --------------------------------------------------------------- 0 Major number 1 Minor number 2 Patchlevel number Additionally, the following constants are defined in the `gdbm.h' file: GDBM_VERSION_MAJOR Major number. GDBM_VERSION_MINOR Minor number. GDBM_VERSION_PATCH Patchlevel number. These can be used to verify whether the header file matches the library. To compare two split-out version numbers, use the following function: -- gdbm interface: int gdbm_version_cmp (int const A[3], int const B[3]) Compare two version numbers. Return `-1' if A is less than B, `1' if A is greater than B and `0' if they are equal. Comparison is done from left to right, so that: a = { 1, 8, 3 }; b = { 1, 8, 3 }; gdbm_version_cmp (a, b) => 0 a = { 1, 8, 3 }; b = { 1, 8, 2 }; gdbm_version_cmp (a, b) => 1 a = { 1, 8, 3 }; b = { 1, 9. 0 }; gdbm_version_cmp (a, b) => -1 File: gdbm.info, Node: Compatibility, Next: Bugs, Prev: Variables, Up: Top 20 Compatibility with standard `dbm' and `ndbm'. ************************************************ `Gdbm' includes a compatibility layer, which provides traditional `ndbm' and older `dbm' functions. The layer is compiled and installed if the `--enable-libgdbm-compat' option is used when configuring the package. The compatibility layer consists of two header files: `ndbm.h' and `dbm.h' and the `libgdbm_compat' library. Older programs using `ndbm' or `dbm' interfaces can use `libgdbm_compat' without any changes. To link a program with the compatibility library, add the following two options to the `cc' invocation: `-lgdbm -lgdbm_compat'. The `-L' option may also be required, depending on where `gdbm' is installed, e.g.: cc ... -L/usr/local/lib -lgdbm -lgdbm_compat Databases created and manipulated by the compatibility interfaces consist of two different files: `FILE.dir' and `FILE.pag'. This is required by the POSIX specification and corresponds to the traditional usage. Note, however, that despite the similarity of the naming convention, actual data stored in these files has not the same format as in the databases created by other `dbm' or `ndbm' libraries. In other words, you cannot access a standard UNIX `dbm' file with GNU `dbm'! GNU `dbm' files are not `sparse'. You can copy them with the usual `cp' command and they will not expand in the copying process. * Menu: * ndbm:: NDBM interface functions. * dbm:: DBM interface functions. File: gdbm.info, Node: ndbm, Next: dbm, Up: Compatibility 20.1 NDBM interface functions. ============================== The functions below implement the POSIX `ndbm' interface: -- ndbm: DBM * dbm_open (char *FILE, int FLAGS, int MODE) Opens a database. The FILE argument is the full name of the database file to be opened. The function opens two files: `FILE.pag' and `FILE.dir'. The FLAGS and MODE arguments have the same meaning as the second and third arguments of `open' (*note open a file: (open(2))open.), except that a database opened for write-only access opens the files for read and write access and the behavior of the `O_APPEND' flag is unspecified. The function returns a pointer to the `DBM' structure describing the database. This pointer is used to refer to this database in all operations described below. Any error detected will cause a return value of `NULL' and an appropriate value will be stored in `gdbm_errno' (*note Variables::). -- ndbm: void dbm_close (DBM *DBF) Closes the database. The DBF argument must be a pointer returned by an earlier call to `dbm_open'. -- ndbm: datum dbm_fetch (DBM *DBF, datum KEY) Reads a record from the database with the matching key. The KEY argument supplies the key that is being looked for. If no matching record is found, the `dptr' member of the returned datum is `NULL'. Otherwise, the `dptr' member of the returned datum points to the memory managed by the compatibility library. The application should never free it. -- ndbm: int dbm_store (DBM *DBF, datum KEY, datum CONTENT, int MODE) Writes a key/value pair to the database. The argument DBF is a pointer to the `DBM' structure returned from a call to `dbm_open'. The KEY and CONTENT provide the values for the record key and content. The MODE argument controls the behavior of `dbm_store' in case a matching record already exists in the database. It can have one of the following two values: `DBM_REPLACE' Replace existing record with the new one. `DBM_INSERT' The existing record is left unchanged, and the function returns `1'. If no matching record exists in the database, new record will be inserted no matter what the value of the MODE is. -- ndbm: int dbm_delete (DBM *DBF, datum KEY) Deletes the record with the matching key from the database. If the function succeeds, `0' is returned. Otherwise, if no matching record is found or if an error occurs, `-1' is returned. -- ndbm: datum dbm_firstkey (DBM *DBF) Initializes iteration over the keys from the database and returns the first key. Note, that the word `first' does not imply any specific ordering of the keys. If there are no records in the database, the `dptr' member of the returned datum is `NULL'. Otherwise, the `dptr' member of the returned datum points to the memory managed by the compatibility library. The application should never free it. -- ndbm: datum dbm_nextkey (DBM *DBF) Continues the iteration started by `dbm_firstkey'. Returns the next key in the database. If the iteration covered all keys in the database, the `dptr' member of the returned datum is `NULL'. Otherwise, the `dptr' member of the returned datum points to the memory managed by the compatibility library. The application should never free it. The usual way of iterating over all the records in the database is: for (key = dbm_firstkey (dbf); key.ptr; key = dbm_nextkey (dbf)) { /* do something with the key */ } The loop above should not try to delete any records from the database, otherwise the iteration is not guaranteed to cover all the keys. *Note Sequential::, for a detailed discussion of this. -- ndbm: int dbm_error (DBM *DBF) Returns the error condition of the database: `0' if no errors occurred so far while manipulating the database, and a non-zero value otherwise. -- ndbm: void dbm_clearerr (DBM *DBF) Clears the error condition of the database. -- ndbm: int dbm_dirfno (DBM *DBF) Returns the file descriptor of the `dir' file of the database. It is guaranteed to be different from the descriptor returned by the `dbm_pagfno' function (see below). The application can lock this descriptor to serialize accesses to the database. -- ndbm: int dbm_pagfno (DBM *DBF) Returns the file descriptor of the `pag' file of the database. See also `dbm_dirfno'. -- ndbm: int dbm_rdonly (DBM *DBF) Returns `1' if the database DBF is open in a read-only mode and `0' otherwise. File: gdbm.info, Node: dbm, Prev: ndbm, Up: Compatibility 20.2 DBM interface functions. ============================= The functions below are provided for compatibility with the old UNIX `DBM' interface. Only one database at a time can be manipulated using them. -- dbm: int dbminit (char *FILE) Opens a database. The FILE argument is the full name of the database file to be opened. The function opens two files: `FILE.pag' and `FILE.dir'. If any of them does not exist, the function fails. It never attempts to create the files. The database is opened in the read-write mode, if its disk permissions permit. The application must ensure that the functions described below in this section are called only after a successful call to `dbminit'. -- dbm: int dbmclose (void) Closes the database opened by an earlier call to `dbminit'. -- dbm: datum fetch (datum KEY) Reads a record from the database with the matching key. The KEY argument supplies the key that is being looked for. If no matching record is found, the `dptr' member of the returned datum is `NULL'. Otherwise, the `dptr' member of the returned datum points to the memory managed by the compatibility library. The application should never free it. -- dbm: int store (datum KEY, datum CONTENT) Stores the key/value pair in the database. If a record with the matching key already exists, its content will be replaced with the new one. Returns `0' on success and `-1' on error. -- dbm: int delete (datum KEY) Deletes a record with the matching key. If the function succeeds, `0' is returned. Otherwise, if no matching record is found or if an error occurs, `-1' is returned. -- dbm: datum firstkey (void) Initializes iteration over the keys from the database and returns the first key. Note, that the word `first' does not imply any specific ordering of the keys. If there are no records in the database, the `dptr' member of the returned datum is `NULL'. Otherwise, the `dptr' member of the returned datum points to the memory managed by the compatibility library. The application should never free it. -- dbm: datum nextkey (datum KEY) Continues the iteration started by a call to `firstkey'. Returns the next key in the database. If the iteration covered all keys in the database, the `dptr' member of the returned datum is `NULL'. Otherwise, the `dptr' member of the returned datum points to the memory managed by the compatibility library. The application should never free it. File: gdbm.info, Node: Bugs, Next: Resources, Prev: Compatibility, Up: Top 21 Problems and bugs. ********************* If you have problems with GNU `dbm' or think you've found a bug, please report it. Before reporting a bug, make sure you've actually found a real bug. Carefully reread the documentation and see if it really says you can do what you're trying to do. If it's not clear whether you should be able to do something or not, report that too; it's a bug in the documentation! Before reporting a bug or trying to fix it yourself, try to isolate it to the smallest possible input file that reproduces the problem. Then send us the input file and the exact results `gdbm' gave you. Also say what you expected to occur; this will help us decide whether the problem was really in the documentation. Once you've got a precise problem, send e-mail to <bug-gdbm AT gnu.org>. Please include the version number of GNU `dbm' you are using. You can get this information by printing the variable `gdbm_version' (*note Variables::). Non-bug suggestions are always welcome as well. If you have questions about things that are unclear in the documentation or are just obscure features, please report them too. You may contact the authors and maintainers by e-mail: <phil AT cs.edu>, <downsj AT downsj.com>, <gray AT gnu.ua> File: gdbm.info, Node: Resources, Next: GNU Free Documentation License, Prev: Bugs, Up: Top 22 Additional resources *********************** For the latest updates and pointers to additional resources, visit `http://www.gnu.org/software/gdbm'. In particular, a copy of `gdbm' documentation in various formats is available online at `http://www.gnu.org/software/gdbm/manual'. Latest versions of `gdbm' can be downloaded from anonymous FTP: `ftp://ftp.gnu.org/gnu/gdbm', or via HTTP from `http://ftp.gnu.org/gnu/gdbm', or from any GNU mirror worldwide. See `http://www.gnu.org/order/ftp.html', for a list of mirrors. To track `gdbm' development, visit `http://puszcza.gnu.org.ua/projects/gdbm'. File: gdbm.info, Node: GNU Free Documentation License, Next: Index, Prev: Resources, Up: Top Appendix A GNU Free Documentation License ***************************************** Version 1.3, 3 November 2008 Copyright (C) 2000, 2001, 2002, 2007, 2008, 2011 Free Software Foundation, Inc. `http://fsf.org/' Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. PREAMBLE The purpose of this License is to make a manual, textbook, or other functional and useful document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others. 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The operator of an MMC Site may republish an MMC contained in the site under CC-BY-SA on the same site at any time before August 1, 2009, provided the MMC is eligible for relicensing. ADDENDUM: How to use this License for your documents ==================================================== To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page: Copyright (C) YEAR YOUR NAME. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled ``GNU Free Documentation License''. If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the "with...Texts." line with this: with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software. File: gdbm.info, Node: Index, Prev: GNU Free Documentation License, Up: Top Index ***** [index] * Menu: * -g, testgdbm option: testgdbm. (line 9) * -n, testgdbm option: testgdbm. (line 19) * -r, testgdbm option: testgdbm. (line 16) * 1: shell. (line 118) * <: shell. (line 125) * ?: shell. (line 200) * _GDBM_MAX_ERRNO: Variables. (line 28) * _GDBM_MIN_ERRNO: Variables. (line 25) * A: shell. (line 143) * a: shell. (line 142) * avail: shell. (line 141) * B: shell. (line 148) * b: shell. (line 147) * bucket: shell. (line 146) * C: shell. (line 153) * c: shell. (line 63) * ca: shell. (line 172) * cache: shell. (line 171) * close-on-exec: Open. (line 48) * closing database: Close. (line 6) * co: shell. (line 62) * command line options, testgdbm: invocation. (line 6) * compatibility layer: Compatibility. (line 6) * count: shell. (line 61) * creating a database, testgdbm: testgdbm. (line 19) * cu: shell. (line 152) * current: shell. (line 151) * D: shell. (line 158) * d: shell. (line 68) * da: shell. (line 191) * data-zero: shell. (line 190) * database options: Options. (line 6) * database reorganization: Reorganization. (line 6) * database synchronization: Sync. (line 6) * database, closing: Close. (line 6) * database, opening or creating: Open. (line 6) * DBM functions: dbm. (line 6) * dbm.h: Compatibility. (line 11) * dbm_clearerr: ndbm. (line 98) * dbm_close: ndbm. (line 26) * dbm_delete: ndbm. (line 57) * dbm_dirfno: ndbm. (line 101) * dbm_error: ndbm. (line 93) * dbm_fetch: ndbm. (line 30) * dbm_firstkey: ndbm. (line 62) * DBM_INSERT: ndbm. (line 49) * dbm_nextkey: ndbm. (line 72) * dbm_open: ndbm. (line 9) * dbm_pagfno: ndbm. (line 109) * dbm_rdonly: ndbm. (line 113) * DBM_REPLACE: ndbm. (line 46) * dbm_store: ndbm. (line 39) * dbmclose: dbm. (line 23) * dbminit: dbm. (line 11) * de: shell. (line 67) * default database, testgdbm: testgdbm. (line 9) * delete <1>: dbm. (line 42) * delete: shell. (line 66) * deleting records: Delete. (line 6) * deletion in iteration loops: Sequential. (line 56) * di: shell. (line 157) * dir: shell. (line 156) * dir file: Compatibility. (line 22) * e: shell. (line 72) * error codes: Error codes. (line 6) * error strings: Errors. (line 6) * export <1>: shell. (line 71) * export: Flat files. (line 6) * F: shell. (line 163) * f: shell. (line 82) * fe: shell. (line 81) * fetch <1>: dbm. (line 26) * fetch: shell. (line 80) * fetching records: Fetch. (line 6) * fi: shell. (line 117) * first: shell. (line 116) * firstkey: dbm. (line 48) * Flat file format: Flat files. (line 6) * GDBM_BAD_FILE_OFFSET: Error codes. (line 117) * GDBM_BAD_MAGIC_NUMBER: Error codes. (line 48) * GDBM_BAD_OPEN_FLAGS: Error codes. (line 121) * GDBM_BLOCK_SIZE_ERROR: Error codes. (line 15) * GDBM_BYTE_SWAPPED: Error codes. (line 112) * GDBM_CACHESIZE: Options. (line 30) * GDBM_CANNOT_REPLACE: Error codes. (line 92) * GDBM_CANT_BE_READER: Error codes. (line 56) * GDBM_CANT_BE_WRITER: Error codes. (line 61) * GDBM_CENTFREE: Options. (line 78) * GDBM_CLOEXEC: Open. (line 48) * gdbm_close: Close. (line 10) * GDBM_COALESCEBLKS: Options. (line 92) * gdbm_delete: Delete. (line 9) * gdbm_delete and sequential access: Sequential. (line 56) * GDBM_EMPTY_DATABASE: Error codes. (line 52) * gdbm_errlist: Variables. (line 17) * gdbm_errno: Variables. (line 9) * gdbm_exists: Fetch. (line 37) * gdbm_export: Flat files. (line 25) * GDBM_FASTMODE: Options. (line 52) * gdbm_fdesc: Locking. (line 14) * gdbm_fetch: Fetch. (line 7) * GDBM_FILE_EOF: Error codes. (line 132) * GDBM_FILE_OPEN_ERROR: Error codes. (line 19) * GDBM_FILE_READ_ERROR: Error codes. (line 41) * GDBM_FILE_SEEK_ERROR: Error codes. (line 34) * GDBM_FILE_STAT_ERROR: Error codes. (line 125) * GDBM_FILE_WRITE_ERROR: Error codes. (line 27) * gdbm_firstkey: Sequential. (line 14) * GDBM_GETCACHESIZE: Options. (line 40) * GDBM_GETCOALESCEBLKS: Options. (line 104) * GDBM_GETDBNAME: Options. (line 127) * GDBM_GETFLAGS: Options. (line 44) * GDBM_GETMAXMAPSIZE: Options. (line 114) * GDBM_GETMMAP: Options. (line 123) * GDBM_GETSYNCMODE: Options. (line 74) * GDBM_ILLEGAL_DATA: Error codes. (line 98) * gdbm_import: Flat files. (line 46) * GDBM_INSERT: Store. (line 23) * GDBM_ITEM_NOT_FOUND: Error codes. (line 83) * GDBM_MALLOC_ERROR: Error codes. (line 12) * GDBM_NEWDB <1>: Flat files. (line 35) * GDBM_NEWDB: Open. (line 28) * gdbm_nextkey: Sequential. (line 24) * GDBM_NO_ERROR: Error codes. (line 9) * GDBM_NOLOCK <1>: Locking. (line 6) * GDBM_NOLOCK: Open. (line 40) * GDBM_NOMMAP: Open. (line 40) * gdbm_open: Open. (line 9) * GDBM_OPT_ALREADY_SET: Error codes. (line 102) * GDBM_OPT_ILLEGAL: Error codes. (line 107) * GDBM_READER: Open. (line 28) * GDBM_READER_CANT_DELETE: Error codes. (line 65) * GDBM_READER_CANT_REORGANIZE: Error codes. (line 75) * GDBM_READER_CANT_STORE: Error codes. (line 70) * gdbm_reorganize: Reorganization. (line 9) * GDBM_REORGANIZE_FAILED: Error codes. (line 88) * GDBM_REPLACE: Store. (line 23) * GDBM_SETCACHESIZE: Options. (line 30) * GDBM_SETCENTFREE: Options. (line 78) * GDBM_SETCOALESCEBLKS: Options. (line 92) * GDBM_SETMAXMAPSIZE: Options. (line 108) * GDBM_SETMMAP: Options. (line 118) * gdbm_setopt: Options. (line 11) * GDBM_SETSYNCMODE: Options. (line 61) * gdbm_store: Store. (line 8) * gdbm_strerror: Errors. (line 9) * gdbm_sync: Sync. (line 15) * GDBM_SYNC <1>: Sync. (line 6) * GDBM_SYNC: Open. (line 40) * GDBM_SYNCMODE: Options. (line 61) * GDBM_UNKNOWN_UPDATE: Error codes. (line 80) * gdbm_version: Variables. (line 31) * gdbm_version_cmp: Variables. (line 61) * GDBM_VERSION_MAJOR: Variables. (line 45) * GDBM_VERSION_MINOR: Variables. (line 48) * gdbm_version_number: Variables. (line 34) * GDBM_VERSION_PATCH: Variables. (line 51) * GDBM_WRCREAT <1>: Flat files. (line 35) * GDBM_WRCREAT: Open. (line 28) * GDBM_WRITER: Open. (line 28) * gdbmexport: gdbmexport. (line 6) * H: shell. (line 168) * ha: shell. (line 167) * hash: shell. (line 166) * hea: shell. (line 162) * header: shell. (line 161) * hel: shell. (line 199) * help: shell. (line 198) * i: shell. (line 86) * import <1>: shell. (line 85) * import: Flat files. (line 6) * interactive mode, testgdbm: shell. (line 6) * iterating over records: Sequential. (line 6) * iteration and gdbm_delete: Sequential. (line 56) * iteration loop: Sequential. (line 36) * iteration loop, using NDBM: ndbm. (line 79) * junk.gdbm: testgdbm. (line 9) * K: shell. (line 173) * k: shell. (line 136) * key-zero: shell. (line 135) * l: shell. (line 92) * libgdbm_compat: Compatibility. (line 11) * list: shell. (line 91) * locking: Locking. (line 6) * looking up records: Fetch. (line 6) * n: shell. (line 96) * NDBM functions: ndbm. (line 6) * ndbm.h: Compatibility. (line 11) * next: shell. (line 95) * nextkey: dbm. (line 58) * opening the database: Open. (line 6) * options, database: Options. (line 6) * pag file: Compatibility. (line 22) * PAGER: shell. (line 45) * pager, testgdbm: shell. (line 45) * q: shell. (line 107) * quit: shell. (line 106) * r: shell. (line 132) * rea: shell. (line 124) * read: shell. (line 123) * read-only mode, testgdbm: testgdbm. (line 16) * record, deleting: Delete. (line 6) * record, fetching: Fetch. (line 6) * records, iterating over: Sequential. (line 6) * records, storing: Store. (line 6) * records, testing existence: Fetch. (line 34) * reo: shell. (line 131) * reorganization, database: Reorganization. (line 6) * reorganize: shell. (line 130) * S: shell. (line 178) * s: shell. (line 112) * sequential access: Sequential. (line 6) * sequential access, using NDBM: ndbm. (line 79) * sta: shell. (line 177) * status: shell. (line 176) * sto: shell. (line 111) * store <1>: dbm. (line 35) * store: shell. (line 110) * storing records: Store. (line 6) * synchronization, database: Sync. (line 6) * testgdbm: testgdbm. (line 6) * v: shell. (line 187) * version: shell. (line 186) * version number: Variables. (line 30) * Z: shell. (line 192) * z: shell. (line 137)
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