RestoreSavePoint

Undo transaction operations back to a savepoint.

Short Name

TRANRST()

Type

Low-level data file function

Declaration

COUNT RestoreSavePoint(COUNT savpnt)

Description

RestoreSavePoint() rolls the current transaction back to a previously defined savepoint created with a call to SetSavePoint(). savpnt is the savepoint to roll back to, and is the value returned by the call to SetSavePoint(). This allows you to back up in a transaction to a particular point, without having to Abort() or Commit() the entire transaction. For a complete discussion of this process please see “Data Integrity” in the c-tree Plus Programmer’s Reference Guide.

savpnt can also be specified as a small negative number. -1 means go back to the most current savepoint. -2 means go back one more, etc.

RestoreSavePoint() also clears errors that have occurred since the savepoint.

Return

Value	Symbolic Constant	Explanation
0	NO_ERROR	No error occurred.
71	TNON_ERR	There is no active transaction pending.

See c-tree Plus Error Codes for a complete listing of valid c-tree Plus error values.

Example

COUNT     savepoint;


void domaster() {

    Begin( ctENABLE | ctTRNLOG );   /* start transaction with locks  */

    while( another() ); {         /* get next record to add        */

        savepoint = SetSavePoint();

                         /* get save point at beginning of each master record */

        if ( add_master() < 0 )

            Abort();     /* RestoreSavePoint if can't add master rec          */

        dodetail();      /* process detail records                            */

    if ( Commit(ctFREE) )

        printf("\nError %d in transaction",uerr_cod);

    return;


void dodetail() {

    while( moredetail() ); {       /*get next detail record to add */

        if ( add_detail()<0 ) {    /* add details, if possible     */

            RestoreSavePoint( savepoint ) /* with error, return to savept */

            return;