STRMESSAGE Function

PV-WAVE Foundation > Reference Guide > Procedure and Function Reference: S > STRMESSAGE Function

STRMESSAGE Function

Returns the text of the error message specified by the input error number.

Usage

result = STRMESSAGE(errno)

Input Parameters

errno—The error number for which the message text is desired.

Returned Value

result—The text of the error message specified by errno.

Keywords

None.

Discussion

This function is especially useful in conjunction with the !Err system variable, which always contains the error number of the last error.

However, you should take care not to make the assumption in your programs that certain error numbers always correspond to certain error messages, as this correspondence may change as PV‑WAVE is modified over time.

Example

The following procedure uses function STRMESSAGE to display the error message associated with an input/output error trapped by procedure ON_IOERROR.

; Define a function to read, and return a 100-element,

; floating-point array.

FUNCTION strmessage_ex1, file_name

   ; Declare error label.

   ON_IOERROR, bad

   ; Open the file and use the Get_Lun keyword to allocate a

   ; logical file unit.

   OPENR, unit, file_name, /Get_Lun

   ; Define data array.

   a = FLTARR(100)

   ; Read data.

   READU, unit, a

   ; Clean up and return.

   GOTO, DONE

   ; Exception label.

BAD:

   ; Print the error message associated with the error number in

   ; !ERROR. Note that STRMESSAGE is used to display the message.

     PRINT, "STRMESSAGE: " + STRMESSAGE(!ERROR)

DONE:

   ; Close and free the input/output unit.

   FREE_LUN, unit

   ; Return result. Variable a is undefined if an error occurred.

   RETURN, a

END