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#include <db.h>int db_env_create(DB_ENV **dbenvp, u_int32_t flags);
The DB_ENV object is the handle for a Berkeley DB environment -- a collection including support for some or all of caching, locking, logging and transaction subsystems, as well as databases and log files. Methods of the DB_ENV handle are used to configure the environment as well as to operate on subsystems and databases in the environment.
DB_ENV handles are free-threaded if the DB_THREAD flag is specified to the DB_ENV->open method when the environment is opened. The DB_ENV handle should not be closed while any other handle remains open that is using it as a reference (for example, DB or DB_TXN). Once either the DB_ENV->close or DB_ENV->remove methods are called, the handle may not be accessed again, regardless of the method's return.
The db_env_create function creates a DB_ENV structure that is the handle for a Berkeley DB environment. This function allocates memory for the structure, returning a pointer to the structure in the memory to which dbenvp refers. To release the allocated memory and discard the handle, call the DB_ENV->close or DB_ENV->remove methods.
The DB_ENV handle contains a special field, "app_private", which is declared as type "void *". This field is provided for the use of the application program. It is initialized to NULL and is not further used by Berkeley DB in any way.
The db_env_create method returns a non-zero error value on failure and 0 on success.
The flags parameter must be set to 0 or the following value:The DB_RPCCLIENT flag indicates to the system that this environment is remote on a server. The use of this flag causes the environment methods to use functions that call a server instead of local functions. Prior to making any environment or database method calls, the application must call the DB_ENV->set_rpc_server function to establish the connection to the server.
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