Save a database image to an external file.
MCO_RET mco_db_xml_export( /*IN*/ mco_trans_h t,
/*IN*/ void * stream_handle,
/*IN*/ mco_stream_write output_stream_writer );
|
t |
The |
| stream_handle | Handle to the output stream. |
|
output_stream_writer |
This function exports database data to an output stream. The runtime calls the application-defined handler to manage the output stream.
It is the application’s responsibility to open the output stream, in the proper mode to stream binary data, and to ensure that there is adequate space at the destination to hold the database. Indexes are not streamed; they will be rebuilt when the database is reloaded. See the control structure stream writer for further details.
| MCO_S_OK | The database was closed successfully. |
| MCO_E_WRITE_STREAM | Error writing to output stream. |
Application snippet:
const char * dbname = "SimpleDb";
/* Stream writer with prototype mco_stream_write */
mco_size_sig_t file_writer( void *stream_handle /* FILE * */, const void *from, mco_size_t nbytes )
{
FILE *f = (FILE *)stream_handle;
mco_size_sig_t nbs;
nbs = fwrite( from, 1, nbytes, f );
return nbs;
}
int main(int argc, char* argv[])
{
mco_db_h db;
MCO_RET rc;
mco_device_t dev;
mco_db_params_t db_params;
mco_trans_h t;
FILE * f;
if( (rc = mco_runtime_start()) != MCO_S_OK)
exit(-1);
rc = mco_db_open_dev( dbname, simple_get_dictionary(), &dev, 1, &db_params );
if ( MCO_S_OK != rc )
{
rc = mco_db_connect(dbname, &db);
...
/* Export database */
f = fopen( "db.xml", "wb" );
if ( f == 0 )
{
printf( "\n\t Can't open output file for streaming\n");
}
else
{
rc = mco_trans_start(db, MCO_READ_ONLY, MCO_TRANS_FOREGROUND, &t);
if ( MCO_S_OK == rc )
{
rc = mco_db_xml_export( t, f, file_writer );
mco_trans_rollback( t );
fclose( f );
...
}
}
...
}
}