on error()

on_error()

Sets the AEL function to be called in case of an error. If the argument is omitted or is NULL, then the current error handler is removed. The address of the old error handler function is returned. If the argument is not an AEL function address, the function fails and reports an error.

When an error occurs, the error handler function is called and passes the following:

Error code, an integer indicating line in message file. Common run time error codes for the class "AEL" are listed in Common Run Time Error Codes.
Error class, a string indicating name of message file
Operation code, an integer indicating the type of operation occurring. The AEL operation codes are listed in AEL Operation Codes.
File name, a string identifying the file where error occurred.
Line, an integer indicating the line number where error occurred (starting at 1).
Column, an integer indicating the column number where error occurred (starting at 1).

The error handling function should return a value of NULL to ignore the error (after taking appropriate corrective action) or a non-zero integer value to allow AEL to continue error processing. Returns a function address.

Syntax:

on_error( [func] );

where

func is the address of error handling function.

Example:

defun report_error( code, class, op, line, col)
{
      fputs( stderr, strcat("Error occurred:", class, code, " at ", line, "/", col));
      return TRUE;
}
on_error( report_error);

Common Run Time Error Codes

Code	Definition
300	Integer parameter value was required
301	Real parameter value was required
302	Two numeric parameters are required
303	String parameter value was required
304	Incorrect type of parameter value
305	Parameters cannot be matched
306	Stack reference to value not on stack
307	Wrong number of parameters passed
308	Numeric parameter expected
309	Function address missing for call
310	Function address not executable
311	Word reference parameter expected
312	Bad frame reference */
313	Integer divide by zero
314	Real divide by zero
315	Complex divide by zero
316	Illegal return value from compare function
317	Values not comparable
318	Log of negative number
319	Log of zero
320	Square root of negative number

AEL Operation Codes

Code	Definition	Code	Definition
0	discard return value	16	assign
1	logical OR	17	dereference word
2	logical AND	18	call function
3	logical NOT	19	call function, discard return value
4	logical test ==	20	return from function
5	logical test !=	21	branch on TRUE
6	logical test >=	25	bitwise AND
7	logical test <=	26	bitwise exclusive OR
8	logical test >	27	bitwise OR
9	logical test <	28	bitwise ones compliment
10	add	29	bitwise left shift
11	subtract	30	bitwise right shift
12	multiply	31	pre-increment
13	modulus divide	32	pre-decrement
14	divide	33	post-increment
15	negate	34	post-decrement

Where Used:

Measurement Expressions (Data Display equations and Schematic MeasEqns), Schematic, Layout, Simulation, GUI