multi-thread win32 programming

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any chance and you can answer my 2nd question about the blinking windows? or is it too complex? coz i dont have to do it but i would like to.....

Well, Windows programming is difficult. It's hard to say right out of the bat what's wrong.

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yes, it is difficult.. but ive seen it happen pretty much on every program me or any of my friends wrote so i though it was something to do with the time it takes the program to redrew everything on resize but then again on every commercial program it doesnt happen... so there must be something to be done. but thats ok for now. i can give it a rest and figure it out at another time.

This tutorial covers common causes and fixes for flickering windows.

http://catch22.net/tuts/flicker.asp

gg

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Originally Posted by Elysia

Avoid global variables! They are not thread safe, sometimes they aren't optimized and they are hard to keep track of and easily creates bugs!
Just an advice for you.

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Elysa, you are a programming noob, why the hell don't you know anything! :/

If you need to use a global variable with a thread, declare the varible as volatile.
Just be aware that multiple threads may access it at the same time. If two or more threads need to use a shared item, use CRITICAL_SECTION's.

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Originally Posted by abachler

Elysa, you are a programming noob, why the hell don't you know anything! :/

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Yeah, right :rolleyes:

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If you need to use a global variable with a thread, declare the varible as volatile.
Just be aware that multiple threads may access it at the same time. If two or more threads need to use a shared item, use CRITICAL_SECTION's.

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This was discussed before. Volatile is pretty much compiler implementation defined, unknown territory. And you don't need volatile if there's just one thread accessing it!
If two threads are accessing it, THEN you need locks.
But this still makes them bad because of other reasons I pointed out. Some globals just aren't optimized, and they can create hard-to-maintain code in larger projects.

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Originally Posted by Elysia

This was discussed before.

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and for all the reasons that where discussed, globals are not inherently bad. People misuse globals just as they misuse templates or classes, that doesnt make them bad. Poor programming does not make a feature 'bad'. There are many times when globals can easily solve a problem that would otherwise be convoluted or quite frankly impossible to solve. Ultimately there will always be at least some data that MUST be global for any serious project to function. If I have 50 thread functions that all access a common database, I certainly do NOT want to maintain that database seperately for each thread. The simple solution is a global variable. If someone has problems reading -

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extern LPVOID pDatabase;

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then they shouldnt be programming in the first place. If they cant find the initial declaration, perhaps they need to check oh, I dont know 'declarations.cpp' or some such.

Crappy programmers shouldn't breathe, that would save us all a lot of problems with people crying about global variables. If you cant handle globals, or you can't use them properly, then don't use them, but don't make high and mighty claims that they are therefore 'BAD'.

IMO it is a very bad idea to have two threads running on the same UI. Most controls are not thread safe.

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Originally Posted by Codeplug

This tutorial covers common causes and fixes for flickering windows.

http://catch22.net/tuts/flicker.asp

gg

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One thing it misses is to use both

InvalidateRect();//set area to be redrawn
UpdateWindow();//bypass the OS message queue and post directly to the windows callback

This makes the paint message non-queued for faster drawing (as paint messages will be ignored and concatenated in the OS msg queue).

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Originally Posted by Elysia

This was discussed before.

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I believe "this" is in reference to the use of volatile. The volatile keyword has nothing to do with multi-threaded programming....unless your compiler says it does (I only know of one compiler that does).

Discussed before here:
http://cboard.cprogramming.com/showthread.php?t=97344
http://cboard.cprogramming.com/showthread.php?t=97475

gg

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Originally Posted by abachler

and for all the reasons that where discussed, globals are not inherently bad. People misuse globals just as they misuse templates or classes, that doesnt make them bad. Poor programming does not make a feature 'bad'. There are many times when globals can easily solve a problem that would otherwise be convoluted or quite frankly impossible to solve. Ultimately there will always be at least some data that MUST be global for any serious project to function. If I have 50 thread functions that all access a common database, I certainly do NOT want to maintain that database seperately for each thread. The simple solution is a global variable. If someone has problems reading -

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extern LPVOID pDatabase;

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then they shouldnt be programming in the first place. If they cant find the initial declaration, perhaps they need to check oh, I dont know 'declarations.cpp' or some such.

Crappy programmers shouldn't breathe, that would save us all a lot of problems with people crying about global variables. If you cant handle globals, or you can't use them properly, then don't use them, but don't make high and mighty claims that they are therefore 'BAD'.

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I do agree, but usually they are misused. If they didn't have a purpose, they wouldn't exist, obviously.

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Originally Posted by Codeplug

I believe "this" is in reference to the use of volatile. The volatile keyword has nothing to do with multi-threaded programming....unless your compiler says it does (I only know of one compiler that does).

Discussed before here:
http://cboard.cprogramming.com/showthread.php?t=97344
http://cboard.cprogramming.com/showthread.php?t=97475

gg

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That's mostly what I was referring to. Volatile is a tricky subject. I don't use them at all and it works fine. So the must have or not can be a tricky question already discussed to great lengths.