If I use Try, the <COLOR color="#FF0000">error passes by</COLOR>… If i  remove the word Try THEN <COLOR color="#008000">the error is catched</COLOR>.

How to use Try and what is the need if the real catch occurs without Try

Consider the following code: -

TIP: - To get nice looking code below use the 'gb' button not the '</>' button


If the file does not exist, a warning is given, otherwise the text in the file is printed.

Finally and Catch are part of the Error handling routines.

If you do not use "Try" then the Finally and Catch statements are used as expected.

using Try is for suppressing the normal error management. any error can then be detected yourself by checking "Error" (as Cogier has shown) but an error will not be raised, that's the point of "Try"

it can also be useful for just suppressing errors and can make for faster code. like these 2 statements


probably the first one is faster.

 Interesting

thanks 2 both guys

 In most languages Try means "get the error" (to be treated in catch), in gambas it means "don't bother me".

I DID like it  lol

 It appears to me that :    Try and error are for a single statement

and :    Finally and Catch are for a block of code

Or have I interpreted it wrong ?

 They are 3 different statements I will let the veterans explain better

What I know:

  Try "tries" to supress the error and you can treat (If you want) checking state of Error. Useful to ignore "not important" errors.

  Catch will only work if there is not a try above (tell me if I am wrong)

  Finally must be used before catch because it can raise another error

The difference between Finally and Catch is that the code under Catch is run only if there is an error (and you didn't use Try). The code under Finally is run if there is an error or if not an error and you have not exited the function using Return

If Finally is used it must be used before Catch

sergioabreu said

  Catch will only work if there is not a try above (tell me if I am wrong)

Not exactly true. Catch will work if an Error is detected on any line that is not "protected" by a Try.

It results the same:

Having

a Try protecting the code that would produce the error

, the Catch in a line below below will not catch THAT ERROR

That's what I meant. A Try just above

thatbruce said

sergioabreu said

  Catch will only work if there is not a try above (tell me if I am wrong)

Not exactly true. Catch will work if an Error is detected on any line that is not "protected" by a Try.

"That is ABOVE the Catch line"

 An error detected in the Catch block "propagates" up through the call stack looking for another Catch (until it finally cr*ps out and aborts the program).
Unless…
There is a top level error handler, I can't remember how it is used?

sergioabreu said

It results the same:

Having

a Try protecting the code that would produce the error

, the Catch in a line below below will not catch THAT ERROR

Code

Try   line that could generate error
Catch do not catch


That's what I meant. A Try just above

Exactly! THAT line is "protected" which means the interpreter ignores any error that occurs when it is executed. Perhaps you are thinking that TRY is working as a block definition. It isn't, it applies to a single line of code. Similarly CATCH and FINALLY aren't blocks either, they are sort of goto targets. If an error is detected in a non-TRY line and there is a CATCH "label" then the interpreter does a jump to the first line in after the CATCH label.
IOW if an error occurs in an unprotected line then execution immediately jumps to the CATCH, nothing in between is executed.

Theoretically, when executing the CATCH code reaches its end, execution should then jump to the FINALLY and execute that code and then RETURN. But I have doubts about that.
<COLOR color="#FF0000">No, that's wrong. The FINALLY chunk is executed before the CATCH chunk.</COLOR>

and another thing..
TRY doesn't always do things the way you may think. It depends on the command you use it on.
For example
can result in weird outcomes.   :?