Debugging

When you are writing complex formulas, it is likely that they will not immediately function as 

intended. Although the compiler tries to catch most of the common mistakes and reports them as 

errors

 or 

warnings

, some mistakes will go unnoticed until you try the formula.

The process of trying a formula and correcting it until it works is called debugging, because you are 

essentially removing bugs (programming mistakes). To debug a formula, you use run time 

messages. 

Run time messages can be generated by a formula while it is executed. They appear in the 

Compiler 

Messages

 tool window, where you can examine them.

To enable run time messages, define the DEBUG symbol. Run time messages are caused by an 

array index that is 

out of bounds

, an assignment of 

incompatible arrays

, or by the 

print function

. 

Here is an example:

int 

a[

4

]

int 

i = 

5

a[i] = 

4              

; out of bounds, no run time message

print

(

"Hello?"

)       

; ignored

$define DEBUG

a[i] = 

3              

; out of bounds, causes run time message

print

(

"Hello, world"

) 

; causes run time message

Use the print function to examine the values of variables while the formula is executed, so you can 

understand why it is not working properly.

By not defining the DEBUG symbol, run time messages are not generated. When you are publishing 

a formula, you should make sure the DEBUG symbol is not defined, since the users of your formula 

will probably not appreciate the run time messages.

Next: 

Optimizations

See Also

print function

Compiler directives

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