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To be clear, this is not a programming question. I don't need help with this, it's just something I don't want to do, which I'm sure other C++ developers can relate to.
I am not using the STL because this has to run on machines with very little RAM, and with questionably compliant headers.
I have a paint routine in my canvas controls that I'm drawing a gradient in. This routine uses alpha-blending between two RGBa8888 or HSVa8888 colors to accommodate creating the gradient. It's relatively simple in practice because my library handles the alpha blending. You just call a blend function and pass it a scaled ratio between 0 and 1. The alpha blending is completely battle tested and used all over the library to do things like anti-alias fonts.
The paint routine more or less works as long as I don't call the blend function to create the gradient. As soon as I add the call, I get corrupted data in my incoming serial stream (handled in a separate C++ implementation file) and the app hangs, pretty reliably. It's about the only reliable thing about it.
C and C++ developers already know where this is headed. 
Heap corruption has reared its ugly head. This is probably related to the fact that I am not using the STL to do anything. A lot of times I wish I was but IoT leaves me little of the STL to practically use.
My options are:
- Rewrite, and maybe prototype using the STL, which at least works on the ESP32 platform. The codebase is pretty small and some of it is reusable.
- Instrument my code for heap testing. This is a pain in my backside, particularly if the heap corruption is coming from my graphics library or my data structures library. I doubt it, but you never know.
- rearchitect my code so it doesn't need dynamic allocations. This would make it far less efficient and probably overflow the .bss segment on less capable devices with all the statically initialized arrays.
Kevin bless IoT development.
Check out my IoT graphics library here:
https://honeythecodewitch/gfx
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Option 1 is for sissies.
Option 2 is for sissies.
Option 3 is for sissies.
Debug you code like real men do and make intense usage of raw memory allocations.
Kidding: I feel your pain. Occasionally I even have to debug someone else's 8051 assembly code.
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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Is it possible to compile the code to run under Windows or Linux?
If so could valgrind or Dr. Memory help find the problem?
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A lot of it will. The tricky issue is the display. It's possible to get it running under DirectX because I wrote a display shim for it, but it's slow.
Check out my IoT graphics library here:
https://honeythecodewitch/gfx
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honey the codewitch wrote: but it's slow.
as long as it helps to find the error... 
M.D.V.
If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
Rating helpful answers is nice, but saying thanks can be even nicer.
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If you are 110% sure that your allocation causes the issue, then go with STL. This probably will be faster than hunting a bug in your code. The third option is not a valid one unless you are doing some strange stuff.
Advertise here – minimum three posts per day are guaranteed.
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Pardon my ignorance. What is "STL"? I only know STL as a geometry format standard.
"A little time, a little trouble, your better day"
Badfinger
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The Standard Template Library. Basically the "runtime library" for C++ (not really a runtime lib but serves the same purpose as those do in other languages)
Check out my IoT graphics library here:
https://honeythecodewitch/gfx
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Got it.
I am old school C programmer, but have been trying to learn C++.
Thanx
"A little time, a little trouble, your better day"
Badfinger
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checked out your website. I have seen it before. VInterest red text on black background. Makes it appear almost 3D. I don't have any arduino hardware. But it's got me interested. Thanx
"A little time, a little trouble, your better day"
Badfinger
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What do you believe to be the root cause of your problem? It sounds like your code is trampling memory. If so, using statically allocated memory could still result in crashes. This kind of bug is hard to find but must be found and fixed. Could the heap implementation itself have a bug? Could a race condition from multi-threading or work done at interrupt level be corrupting the heap?
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I doubt it's anything that complicated. I suspect some foolery in either my lifetime management or somehow, somewhere I'm not copying memory correctly.
At one point - after I ported some of it to use the STL, I needed to pull pointers out of a vector to pass to a function, but that concerned me due to the potential for the vector reallocating, even though I called reserve() - I don't trust the inner machinations of the STL and it's too much to remember all of its intricacies.
Instead I went back to my tried and true new/delete and stashing pointers in my simple_vector class. I don't think that's the problem.
However, there's a lot of spinning plates to balance. Incoming serial data can cause a lot of deallocations and reallocations, and while that is NOT happening while my on_paint callbacks are being summoned, it still makes me nervous.
In the end I'm thinking of a total rewrite of the firmware to see if I can make it more cohesive. I have some ideas.
Check out my IoT graphics library here:
https://honeythecodewitch/gfx
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Time to bring out your rubber duck!
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I traced the code to a routine in my graphics library. I think. I've just run it down and am trying to verify (without a debugger LOL)
Also without much reliable in the way of spew because I'm already using the serial port for communication. I've half bodged a logging system into it, but everything has to be working right for it to function, and i can't get stack traces out of dumps using this.
Check out my IoT graphics library here:
https://honeythecodewitch/gfx
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honey the codewitch wrote: Instrument my code for heap testing.
I never did embedded stuff.
But I did use memory leak testing a lot. Just because, even with discipline, I figured I might have missed something. Reducing the testing to libraries with that in place with unit testing (I use that term very loosely - test the entire library and not just units) allows one to simplify the scope and be more sure of the stability.
Leak is also used loosely. A leak library can test for actual leaks, overwrites, underwrites, unallocated writes, etc.
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A new account posting to a report ... his reply[^] .. could it be...
Also se this post[^]
Graeme
"I fear not the man who has practiced ten thousand kicks one time, but I fear the man that has practiced one kick ten thousand times!" - Bruce Lee
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This the Lounge, I think you mean to go to Spam & Abuse.
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I posted here as the spammer was watching.
Graeme
"I fear not the man who has practiced ten thousand kicks one time, but I fear the man that has practiced one kick ten thousand times!" - Bruce Lee
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You're surely not paranoid Graeme? 
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These aren't the spammers you are looking for.
You can go about your business.
Move along. Move along.
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Do not forget to move the fingers in front of his face...
M.D.V.
If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
Rating helpful answers is nice, but saying thanks can be even nicer.
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Hello all,
We got a new car a week ago, and we are struggling to find the best way to park it in the company garage, no parking slots defined (no painting on the floor), two cars till the last week parked there, now three cars must be parked.
Everybody is open to move the cars.
Do you know of any free solution to find te best position for the three cars given car sizes, the garage size, columns placement and garage door size and placement? Does something like that exist?
Thank you all!
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You've been working with robots too long  , drive into the car park and park in any available space - Simples
In a closed society where everybody's guilty, the only crime is getting caught. In a world of thieves, the only final sin is stupidity. - Hunter S Thompson - RIP
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For only 3 cars, I would just get a copy of the architects' drawing for the garage, cut out paper to scale to represent the cars, and see if they can be made to fit without overlap. If you can't spot a good arrangement by eye, I wouldn't risk parking 3 cars in there.
Why spend time and effort on learning a new software package?
Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.
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Yeah or a whiteboard with magnetic tiles cut to car-size in scale
Or a can of paint, for the floor.
"If we don't change direction, we'll end up where we're going"
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