GWBASIC User's Manual

GW-BASIC User's Guide
ERR and ERL Variables
Purpose:
To return the error code (ERR) and line number (ERL) associated with an error.
Syntax:
v=ERR
v=ERL
Comments:
The variable ERR contains the error code for the last occurrence of an error. All the error codes
and their definitions are listed in Appendix A of the GW-BASIC User's Guide.
The variable ERL contains the line number of the line in which the error was detected.
The ERR and ERL variables are usually used in IF-THEN, or ON ERROR...GOTO, or GOSUB
statements to direct program flow in error trapping.
If the statement that caused the error was a direct mode statement, ERL will contain 65535. To
test if an error occurred in a direct mode statement, use a line of the following form:
IF 65535=ERL THEN ...
Otherwise, use the following:
10 IF ERR=error code THEN...GOSUB 4000
20 IF ERL=line number THEN...GOSUB 4010
Note
If the line number is not on the right side of the relational operator, it cannot be renumbered by
RENUM.
Because ERL and ERR are reserved variables, neither may appear to the left of the equal sign in a
LET (assignment) statement.
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