ON ERROR RESUME NEXT

[den2k88]

It dones't mean they don't have to be used - I use this one too (Yes, I still work with VB6) - but it would be way better to forget them at all. The problems caused by those lines after years they have been developed... basically unfindable bugs because the sucker acts like there is no problem at all. Add this to the fact that the runtimes throws exceptions like candies instead of returning a status value and you have to manage exceptions for perfectly reasonable beahviours, like opening a non existing file. It can happen, it's usually no big deRUNTIME ERROR! CLOSE THE HATCHES! PREPARE FOR IMMERSION NOW!!! So many times you simply stick to On Error Resume Next and then problems arise, after years of seemingly fine running. It's like having a bazooka for home defence. Effective it is, useful also, but it's farking dangerous.

GCS d--- s-/++ a- C++++ U+++ P- L- E-- W++ N++ o+ K- w+++ O? M-- V? PS+ PE- Y+ PGP t++ 5? X R++ tv-- b+ DI+++ D++ G e++>+++ h--- ++>+++ y+++*      Weapons extension: ma- k++ F+2 X If you think 'goto' is evil, try writing an Assembly program without JMP. -- TNCaver When I was six, there were no ones and zeroes - only zeroes. And not all of them worked. -- Ravi Bhavnani

[Sander Rossel]

Most TrySomething (like TryParse) methods swallow exceptions if you don't check for the return value. The if-statement can be just as harmful. Take those huge nested if-else branches. Impossible to test, impossible to change (without breaking everything). So we replace the if-statements with switch/case-statements, same thing happens. We need to loop through some collection, but it's kind of recursive, and now some programmer uses foreach foreach foreach... (yeah, I've seen it happen). In SQL Server when an exception occurs it's more or less swallowed UNLESS you use try-catch (how many programmers know that?). So I now shouldn't use catch, TryParse, if, switch/case, foreach, and SQL Server :) Well, I agree ON ERROR RESUME NEXT is the most useless of them all :)

Read my (free) ebook Object-Oriented Programming in C# Succinctly. Visit my blog at Sander's bits - Writing the code you need. Or read my articles here on CodeProject.

Simplicity is prerequisite for reliability. — Edsger W. Dijkstra

Regards, Sander

[den2k88]

You're absolutely right about the huge nested ifs, I usually tend to modularize a lot and where multiple checks are involved I use a SEQUENCE of if and a cumulative status, so that it becomes

bool keep_going = true;
if (error_cond1) keep_going = false;
if (keep_going && error_cond2) keep_going = false;
...

It's easier to read and modify, also it's not mandatory to have a single cumulative status. Since I work with stdcalls, VB6 and plain old C code on old compilers (long story short: we can't change.) I can't reliably use exceptions outside the deepest functions and being the VS6 stdlib what it is I don't really need them since it's better to stick to CRT functions, which don't have exceptions. Being VS6 CRT what it is many "safe" functions that use SEH exceptions do not exist so I don't use them either.

GCS d--- s-/++ a- C++++ U+++ P- L- E-- W++ N++ o+ K- w+++ O? M-- V? PS+ PE- Y+ PGP t++ 5? X R++ tv-- b+ DI+++ D++ G e++>+++ h--- ++>+++ y+++*      Weapons extension: ma- k++ F+2 X If you think 'goto' is evil, try writing an Assembly program without JMP. -- TNCaver When I was six, there were no ones and zeroes - only zeroes. And not all of them worked. -- Ravi Bhavnani

[Rob Grainger]

I'd say the If..Then..Else statement is pretty clear, amongst many many others. If anything, your example is a little odd, as it really doesn't tell you what it is doing - resume next what? That's not English. (It's also an extremely dodgy technique of error handling, equivalent of enclosing every statement in:

Exception error;
try {
statement;
}
catch (Exception ex) {
error = ex;
}

Which just invites people not to bother checking the result. May as well have a statement like

On Error Keep Calm and Carry On

"If you don't fail at least 90 percent of the time, you're not aiming high enough." Alan Kay.

[Jirajha]

I still love plain old C#.

foreach(var exception in MyExceptionCollection)
try
throw exception;
catch()
continue;

[Herbie Mountjoy]

The best bit about PERL (in fact the only good bit) is On Error DIE Is that why PERL programmers are becoming scarce? We're philosophical about power outages here. A.C. come, A.C. go.

[Jim_Snyder]

When I worked at CompuServe, a coworker wrote some code I was running a test harness on for connecting to the portal. His variable "IBHosed" showed up in the exception if the connection wasn't established.

[Larry Gibson]

catch { // TODO: }

[Lost User]

MOVE CORRESPONDING

Still waiting for one of the "modern languages" to implement that one. (I have to resort to reflection in C#).

[firegryphon]

I think you could also put in a "goto" instead of setting "keep_going" if you want to break up that nested if architecture. :cool::suss: ;P :laugh:

[SeattleC]

I think you need

catch (void) {}

At least in C++ you can throw any type, not just derivations of

class Exception

[jediYL]

You've discovered infinite recursion :-D

// TODO
// catch {
// // TODO
// }

Remain Calm & Continue To Google

[obermd]

If your code is something like this try { statement } catch () {} try { statement } catch () {} ... Then the ON ERROR RESUME NEXT statement makes sense. I actually use it on occasion where I have a short procedure and I want the errors to be consumed and don't care what they are. Doesn't happen often but it does every now and then.

[Antonino Porcino]

RANDOMIZE TIMER