(1) xcall ERRMSG {,errarg}

(2) xcall ERRMSG, msg$, errnum

MAP1 ERRARG

MAP2 ERR'ID,S,6      ! (this field is ignored)

MAP2 ERR'CDE,B,2     ! app-defined error #

MAP2 ERR'MSG,S,50    ! app-defined error message

ERRMSG.SBR is a handy way to handle BASIC error trap reporting. Add the subroutine to your BASIC error trap, and it can display a standardized message at the bottom of the screen (listing information about the error) and log the error to file, and/or retrieve the text associated with the current error. The routine must be set up as an alias to DERR in miame.ini as follows:

ALIAS=ERRMSG:DERR

DERR is a Debug plc routine which is similar to ERRMSG. It is not documented here since we prefer that you use ERRMSG. If you are already using DERR, feel free to continue, but note that it expects four arguments, rather than the 0-2 that ERRMSG expects.

If 0 or 1 argument is passed and a BASIC error has occurred, then ERRMSG ignores the errarg argument (if passed) and displays a three line message at the bottom of the screen relating to the BASIC error, which looks something like this:

* ERROR MESSAGE * TSKAAA    Illegal record number

Error 31 in Line 360 of MYPROG Last File: 5 (ERRMSG.TMP)

Press ESC to Abort

You may also call the ERRMSG directly (i.e. absent any BASIC error) to report application-defined errors. In that case, you must include the errarg parameter, assigning your own values to the fields. For example, consider the following code:

125   ERR'CDE = 142

130   ERR'MSG = "Something bad has happened!"

135   xcall ERRMSG,ERRARG

This would display the following message (where "MYPROG" is the current program name):

* ERROR MESSAGE * TSKAAA    Something bad has happened!

Error 142 in Line 135 of MYPROG

Press RETURN to Continue or Retry

In either of the above cases, the subroutine will also log a similar message to the text file bas:baserr.log.

If two arguments are passed (as in the second sample format above) then it simply retrieves the BASIC error message associated with the specified error number. This can be useful for creating your own error message display within an error trap, since when error trapping is enabled, BASIC no longer displays the error message. (It only supplies you with the error number, last line number, and last channel number, via the ERR(0), ERR(1), and ERR(2) functions.)

ERRMSG (i.e., DERR) uses a Windows-style message box if GUI support is available.