Slide 10.15: Line-by-line anatomy of DB.c (cont.)

Line-by-line Anatomy of DB.c (Cont.)


  DmDatabaseProtect( dbCard, dbID, (locks > 0) ? false : true );

This function Err DmDatabaseProtect( UInt16 cardNo, LocalID dbID, Boolean protect ) increments or decrements the database's protection count.

cardNo: Card number of database to protect/unprotect
dbID: Local ID of database to protect/unprotect
protect: If true, protect count will be incremented. If false, protect count will be decremented.

Returns errNone if no error, or one of the following if an error occurs:


      memErrCardNotPresent
      dmErrROMBased
      dmErrCantFind


      memErrNotEnoughSpace
      dmErrDatabaseNotProtected

This routine can be used to prevent a database from being deleted (by passing true for the protect parameter). All true calls should be balanced by false calls before the application terminates. Use this function if you want to keep a particular record or resource in a database locked down but don't want to keep the database open. This information is kept in the dynamic heap, so all databases are “unprotected” at system reset.


  FrmCustomAlert( ErrorAlert, buf, "...", "..." );

This function UInt16 FrmCustomAlert( UInt16 alertId, const Char *s1, const Char *s2, const Char *s3 ) creates a modal dialog from an alert resource and displays the dialog until the user taps a button in the alert dialog.

alertId: Resource ID of the alert
s1, s2, s3: A button's item number is determined by its order in the alert template; the first button has the item number zero. Up to three strings can be passed to this routine. They are used to replace the variables ^1, ^2 and ^3 that are contained in the message string of the alert resource. If the variables ^1, ^2, and ^3 occur in the message string, do not pass NULL for the arguments s1, s2, and s3. If you want an argument to be ignored, pass the empty string ("").