ON_ERROR_GOTO Procedure

Reference Guide > O Routines > ON_ERROR_GOTO Procedure

Specifies a statement to jump to if an error occurs in the current procedure.

note	If both ON_ERROR and ON_ERROR_GOTO appear before the line in the code that creates the error condition, the ON_ERROR_GOTO takes precedence.

Usage

ON_ERROR_GOTO, label

Input Parameters

label—The name of a label statement to jump to.

note	Do not put a colon after this parameter.

Keywords

None.

Discussion

The ON_ERROR_GOTO procedure transfers program control to the point in the program specified by the label parameter after an error occurs. The label parameter specifies a label, which is an identifier followed by a colon. A label may exist on a line by itself. Labels are explained in the PV‑WAVE Programmer’s Guide.

note	The name null has a special use with this procedure. If the label name is null, the effect of ON_ERROR_GOTO is canceled and normal processing continues.

If an error occurs, an error code is stored in the system variable !Err. In addition, the text of the error message is stored in !Err_String.

Example

This example demonstrates how ON_ERROR_GOTO is used to control program flow after an error is detected.

PRO on_error_goto_ex1

   ; If an error occurs here, go to the

   ; statement label Proc1_Failed.

   ON_ERROR_GOTO, Proc1_Failed

   ; The effect of ON_ERROR_GOTO is canceled,

   ; normal error processing is in effect.

   ON_ERROR_GOTO, null

   RETURN

   Proc1_Failed:

      PRINT, !Err, !Err_String

END