Runtime Recoverable Errors

     Runtime recoverable errors can be expected to happen.  These errors
     generally occur either because of mistakes in your code (e.g., type
     mismatch, or divide by zero) or because of some condition of the
     environment (e.g., out of file handles, file sharing violations, or
     memory low).  These errors can be trapped in the error system and,
     therefore, do not necessarily terminate the application.

     If the default error system is being used in the application, then
     runtime errors are reported in the following format:

     Error | Warning <subSystem>/<subCode> <message text>
        <filename> | <operation>

 Overview on Error Recovery

     Error Recovery Failure

     CA-Clipper's error system depends on communication taking place between
     the error handler and the subsystem that generates the error.  The error
     handler communicates with the subsystem by returning a value indicating
     what the subsystem should attempt to do to recover from the error.  The
     legal values that can be returned are determined by the values contained
     in the error object passed to the error handler for Error:canRetry,
     Error:canDefault, and Error:canSubstitute.  If the error handler returns
     an invalid value to the subsystem (or returns to the subsystem at all
     when these values are all false), then an error recovery failure is
     reported and the application is terminated.  This exit condition always
     has the same format:

     Error recovery failure, <operation> (<line number>)

     User Abort

     The user can abort your application by pressing Alt-C or Ctrl-Break at
     anytime during the execution of your application unless you have
     specifically disabled this feature.  You can disable it with SETCANCEL
     (.F.) or SET(_SET_CANCEL, .F.).

     This exit condition always has the same format:

     Cancelled at: <operation> (<line number>)

     Missing Error Handler

     If code is executed before any ERRORBLOCK() can be installed, an
     unrecoverable error will be generated that indicates that no error
     handler is present.  This usually occurs if there is code in ErrorSys()
     before the ERRORBLOCK() function is called.  All code should be moved
     after this line if possible:

     No ERRORBLOCK() for error at: <operation>
        (<line number>)

 Runtime Recoverable Error Categories

     This section is a summary of runtime recoverable error messages that are
     possible when executing a CA-Clipper application using the supplied
     subsystems.  The messages are divided into categories according to
     subsystem.  Each category is described below, followed by a listing of
     all messages in each category.

     BASE Errors

     BASE error messages indicate errors generated by the Base system.  The
     general format of a BASE error message is as follows:

     Error | Warning BASE/xxxx <message text> <filename> |
        <operation>

     TERM Errors

     TERM error messages indicate errors generated by the Terminal subsystem.
     The general format of a TERM error message is as follows:

     Error | Warning TERM/xxxx <message text> <filename> |
        <operation>

     DBCMD Errors

     DBCMD error messages occur in the database command set, and are
     unrelated to a particular driver.  They occur as a result of command
     usage rather than from a failure of the driver itself.

     Error | Warning DBCMD/xxxx <message text>
        <filename> | <operation>

     DBFCDX Errors

     DBFCDX error messages indicate that an error occurred during a database
     or index operation utilizing the DBFCDX database driver.  The general
     format of a DBFCDX error message is as follows:

     Error | Warning DBFCDX/xxxx <message text>
        <filename> |  <operation>

     DBFMDX Errors

     DBFMDX error messages indicate that an error occurred during a database
     or index operation utilizing the DBFMDX database driver.  The general
     format of a DBFMDX error message is as follows:

     Error | Warning DBFMDX/xxxx <message text>
        <filename> |  <operation>

     DBFNDX Errors

     DBFNDX error messages indicate that an error occurred during a database
     or index operation utilizing the DBFNDX database driver.  The general
     format of a DBFNDX error message is as follows:

     Error | Warning DBFNDX/xxxx <message text>
        <filename> |  <operation>

     DBFNTX Errors

     DBFNTX error messages indicate that an error occurred during a database
     or index operation utilizing the DBFNTX database driver.  The general
     format of a DBFNTX error message is as follows:

     Error | Warning DBFNTX/xxxx <message text>
        <filename> |  <operation>

 Runtime Unrecoverable Errors

     Unrecoverable errors are runtime errors that for some reason cannot make
     use of the error system.  Like runtime errors, it is normal for these
     errors to occur.  This is usually because the system is unable to
     execute the error block.  Almost all of these errors are, therefore,
     related to the environment (e.g., out of memory, errors reading code to
     execute from disk) and can be fixed by making a change to the
     environment.

     Unrecoverable errors always have the same format:

     <operation> (<line number>) Unrecoverable error xxxx:
        <message text>