To artificially cause a built-in error to occur in a program:

1.Enter the error number (as a binary integer or real number) for the error.

2.Enter the DOERR command (PRG ERROR menu).

If DOERR is trapped in an IFERR structure (described in the next topic), execution continues. If it’s not trapped, execution is abandoned at the DOERR command and the error message appears.

To analyze an error in a program:

To get the error number for the last error, execute ERRN (PRG ERROR menu).

To get the error message for the last error, execute ERRM (PRG ERROR menu).

To clear the last-error information, execute ERR0 (PRG ERROR menu).

The error number for a user-defined error is #70000h. See the list of built-in error numbers in appendix A, “Error and Status Messages”.

Example: The following program aborts execution if the list in level 1 contains three objects.

«

OBJ→

IF 3 ==

THEN "3 OBJECTS IN LIST" DOERR END

»

The following table summarizes error trapping commands.

 

 

 

Error Trapping Commands

Key

Programmable

 

Description

 

Command

 

 

 

 

 

 

!° L L %ERROR% :

 

 

 

 

%DOERR%

DOERR

 

Causes an error. For a string in level 1, causes a user-defined error: the

 

 

 

calculator behaves just as if an ordinary error has occurred. For a binary

 

 

 

integer or real number in level 1, causes the corresponding built-in error.

 

 

 

If the error isn’t trapped in an IFERR structure, DOERR displays the

 

 

 

message and abandons program execution. (For 0 in level 1, abandons

 

 

 

execution without updating the error number or message — like −.)

%ERRN%

ERNN

 

Returns the error number, as a binary integer, of the most recent error.

 

 

 

Returns #0 if the error number was cleared by ERR0.

%ERRM%

ERRM

 

Returns the error message (a string) for the most recent error. Returns

 

 

 

an empty string if the error number was cleared by ERR0.

%ERR0%

ERR0

 

Clears the last error number and message.

 

 

 

 

1-34 RPL Programming