dce_db_fetch(3dce)
Retrieves data from a backing store
Synopsis
#include <dce/dce.h>
#include <dce/dbif.h>
void dce_db_fetch(
dce_db_handle_t handle,
void *key,
void *data,
error_status_t *status);
Parameters
Input
handle
A handle, returned from dce_db_open( ), that identifies the backing store being used.
key
A string or UUID that is the key to the item in the backing store. The datatype of key must match the key method that was selected in the flags parameter
to dce_db_open( ) when the backing store was created.
Output
data
A pointer to the returned data.
status
A pointer to the completion status. On successful completion, the routine returns error_status_ok. Otherwise, it returns an error.
Description
The dce_db_fetch( ) routine retrieves data from the backing store that is identified by the handle parameter, which was obtained from
dce_db_open( ). It is a general retrieval routine, interpreting the key parameter according to the type of index with which the backing store was created.
The data parameter is shown as a pointer to an arbitrary data type. In actual use it will be the address of the backing-store-specific data type.
Notes
After calling dce_db_fetch( ), it may be necessary to free some memory, if the call was made outside of an RPC, on the server side. This is done by calling
rpc_sm_client_free( ). (Inside an RPC the memory is allocated through rpc_sm_allocate( ), and is automatically freed.)
Programs that call dce_db_fetch( ) outside of a server operation (for instance, if a server does some backing store initialization, or in a standalone program) must call rpc_sm_enable_allocate( ) first. Indeed, every thread that calls dce_db_fetch( ) must do rpc_sm_allocate( ), but in the server side of an RPC, this is already done.
Errors
The following describes a partial list of errors that might be returned. Refer to the OSF DCE Problem Determination Guide for complete descriptions of all error messages.
db_s_key_not_found
The specified key was not found in the backing store. (This circumstance is not necessarily an error.)
db_s_bad_index_type
The key's type is wrong, or else the backing store is not by name or by UUID.
error_status_ok
The call was successful.
Related Information
Functions: dce_db_fetch_by_name(3dce)