I was reading about free rtos. As I understand whole free rtos program are the combination of header files and source files.
the following are the most important source files in free rtos:
FreeRTOS/Source/tasks.c
FreeRTOS/Source/queue.c
FreeRTOS/Source/list.c
I know the meaning of queue.c and list.c. I know single or multiple task's run on single processor. I don't understand What is work of task.c file in free rtos?
not exactly, FreeRTOS has another one necessary file: port.c (or port.asm). This platform dependent file and it link hardware with software part. This file using functions from tasks.c to provide scheduling mechanism.
For more details please see the official documentation: https://www.freertos.org/FreeRTOS-porting-guide.html
The task.c file contains all the routines for creating and managing FreeRTOS tasks. Some examples are xTaskCreate(), vTaskDelay() etc. See the API reference for the full list FreeRTOS API Reference
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I would love to be able to update my NodeMCU ESP8266-01 OTA, since they're located in awkward spots. I'm by no means an expert regarding the ESP or NodeMCU, but I haven't been able to find anything recent about OTA updates. I found some discussions about it going back to 2015, but it never seems to have been implemented.
I use my ESP with NodeMCU to control a PWM dimmer. I upload a precompiled version of NodeMCU with the NodeMCU Firmware FLasher, and then use ESPlorer to upload a custom lua file called 'init.lua'. I'm not even sure if this is the proper way to do stuff, but it works.
So the main question: Has OTA updating been implemented, or is it possible in some way?
Just to clarify, I don't think I want to update the firmware. As I understand it, firmware is what you build yourself, or on a website like https://nodemcu-build.com. I want to update the lua files that run on the ESP, that you normally upload through a program like ESPlorer.
I found some discussions about it going back to 2015, but it never seems to have been implemented.
Indeed, firmware OTA is not available yet. However, as you probably know, the need for firmware OTA is much lower with the NodeMCU firmware than e.g. with the Arduino platform. I'd argue that you're much less likely in need to replace/upgrade/extend the firmware with its built-in modules than the application code that runs on top of it.
Fortunately, it's quite simple to replace one or several Lua scripts (compiled or uncompiled) on the device and reboot it. All the web and cloud IDEs listed at https://frightanic.com/iot/tools-ides-nodemcu/ offer this. There's even a pending PR that'll bring FTP support to NodeMCU.
For a complete Lua provisioning system take a look at what #TerryE provided at https://github.com/nodemcu/nodemcu-firmware/tree/master/lua_examples/luaOTA
I've attempted to use the two Web IDEs listed in the link provided in Marcel Stör's answer, but I honestly failed to understand how to use either IDE. they also seemed like they weren't exactly what I was looking for, and required a server to connect to, or an extra program, which I wanted to avoid.
Edit: Apparently, I did end up using one of the two Web IDEs in the list. Since it's been a while since I did all this, it's a bit fuzzy in my head.
I eventually stumbled upon this GitHub page, which seemed to provide exactly what I was looking for: The ability to access the Lua files on the ESP through a webbrowser. I have personally changed the ide.lua file around completely, since I needed to call functions from it in the init.lua script. However, I think you can just upload the ide.lua script to the ESP, and add a line containing dofile("ide.lua") to your init.lua file.
If anyone is interested in my changes to, or my implementation of the ide.lua script, you can take a look at my repo Timmiej93 / QuinLED / Program code.
In fact there's a class for that to implement OTA i the NodeMCU its called the ESPhttpUpdate you can refer to ESPhttpUpdate for further details.
I want to open libraries, because currently I want to see the algorithms used for drawing, modify them and implement them in my program. For example: I have tried to create an algorithm on my own for lines. But I failed. And even if I had succeeded, I fear that it might not give the same result as the algorithm in the libraries. And I don't want this to happen. That's why I want to copy the algorithms used for the methods in libraries. And I really hope that this will help me create the application I'm currently working on and with other applications in the future.
I tried to open the libraries with a code editor. But I had troubles finding the libraries- I don't really know where are they placed nor in what files are their codes stored.
How to open a Java library? Or is there a place in the Internet where the code is uploaded?
It sounds like what you want is to get inside the standard Java libraries (so you can see the code for methods like Graphics.drawLine()).
You can download the source files from the same place you got the JDK, if you are on Windows or Linux. For the Mac, see this question. You can even set up Eclipse so that you can debug into that source as if it were your own code.
However, you will probably not find line-drawing code in Java in these libraries - the Graphics implementation will almost certainly use native methods, and may just call existing methods in the OS.
If you are specifically looking for line drawing algorithms, another option would be to look at the Wikipedia page for the Bresenham (aliased) or Wu (antialiased) algorithm.
Edit:
The part of a Graphics2D call that actually puts pixels on the screen is probably inside a system call and therefore the source would not be available.
A java vector graphics library like Batik might have source for some of these algorithms, but probably relies on the Graphics2D calls for most of them. So, you might look for a comprehensive vector graphics library written in a language other than Java, where those graphics calls do not already exist by default.
Alternately, checking the table of contents for a computer graphics book might point you at a variety of algorithms that you could look up on Wikipedia.
For any given library:
Make sure to obey all licenses when using another's code
If you are referring to the Java SDK source code, you can find it here: http://grepcode.com/
If the project is open source, you can usually just get the source from the project website. No problem, though make sure to obey their license.
If the project is NOT open source, well, then you're in a pickle licensing wise, so I do NOT endorse this, however, you would need to use a Java Decompiler such as JD-Gui
As far as what drawing algorithms to use, there are so many different ones (obviously, people have been trying to draw quickly for many many years), your best bet is to figure out exactly what you need to do and then search for that specific need separately. There isn't really a good repository of ALL of them, except maybe wikipedia.
If you are using the libraries they are on your classpath. Check out how to figure out your classpath in whichever IDE you are using and you can find the JARs you depend on. If they are packaged with sources all you need to do it unjar them and look at the sources.
If you don't have access to the sources you can get the code using a Java Decompiler.
If you are trying to look at a standard Java library, see the other answers about getting the source to the JDK.
If you are interested in an open source library (such as something maintained by the Apache project), look on the site of the project for a 'source jar' which you can open with a standard zip utility.
If the library you want is not open source or you cannot find the source for it, you can try to decompile it. If you are using Eclipse, try this decompiler.
I've done some search out there but couldn't find too much really helpful info on it, but could someone try to explain the basic of Java memory maps? Like where/how to use it, it's purpose, and maybe some syntax examples (inputs/outputs types)? I'm taking a Java test soon and this could be one of the topics, but through all of my tutorials Jmap has not come up. Thanks in advance
Edit: I'm referring to the tool: jmap
I would read the man page you have referenced.
jmap prints shared object memory maps or heap memory details of a given process or core file or a remote debug server.
NOTE: This utility is unsupported and may or may not be available in future versions of the JDK. In Windows Systems where dbgeng.dll is not present, 'Debugging Tools For Windows' needs to be installed to have these tools working. Also, PATH environment variable should contain the location of jvm.dll used by the target process or the location from which the Crash Dump file was produced.
http://docs.oracle.com/javase/7/docs/technotes/tools/share/jmap.html
Its not a tool to be played with lightly. You need a good profiler which can read it output as jhat is only useful for trivial programs. (YourKit works just fine for 1+ GB heaps)
tldr; at bottom.
Ok, so once again an interesting problem and I'm looking for a fun and interesting solution.
My current project involves being very modular, meaning the program functionality will be easily changed based on different modules and the program would adapt.
So I started out with the typical route, which is using DLL plugins. Now this is just way to normal, I want to think outside the box a bit.
The modules included in my program are long running campaigns that may take weeks to finish, and there will be many running at a time. So stability is a big issue, so I thought about what Google Chrome does. Processes, not DLLs or threads.
So I have a framework going and I need a way to get some information about each module (which are now EXEs). Now for my DLL framework I was exporting a "Register" function that would fill in some information.
So I thought to myself, hey EXEs can export functions, let's see if that actually works...It doesn't. I did some research into how Windows handles theses things and I don't feel like hacking the PE headers on the fly (but it's the out of the box kind of thinking I'm going for).
I'm planning on using named pipes and CLI parameters to transfer data between the main program and the module exe's. I could use that in a register fashion, but I want to here other peoples thoughts.
tldr: I'm using EXE's instead of DLL's for plugins. Looking for a way to easily export one time information like a exported "Register" function would on a DLL. Thoughts?
You might still consider having the modules written as DLLs with defined entrypoints (e.g., the Register function). Then you write the executable that loads the specified DLL. Your main application would fire off the driver executable and give it a name of a plugin DLL.
That way it is still easy to define and export the set of APIs that must be provided yet still run it as a separate process. The one executable that you write can load the specified DLL and then handle the necessary IPC with the main app.
You could define a protocol via the stdin/stdout, named pipes, sockets, etc.
I have successfully used 'plain' COM for several projects, and objects inheriting from TAutoObject. The bonusses here are IDL; the interopability with .Net, VBA and other non-Delphi things; and the fact that implementors still can choose wether to supply a DLL, an exe, an NT-service, and optionally run hosted over the network (COM+/DCOM). There may be several considerations you should handle about multi-threading and locking, but I found all that I needed to know online.
You can, of course, not use symbols exported by a (running) exe since it is running in another boundary. But, you can load an exe as an image (as you would do with a library) using LoadLibrary(Ex) and then, use the functions exported by the exe. I have tested (just for fun) when debugging PeStudio. See the snapshot below of chrome.exe loaded in the process space of PeStudio.exe using LoadLibrary.
i have an application which call another console application and pass to it some parameters (console app is a video/audio coverter app) ... is there a way to programmatically "spy" or catch the passed paramters other than hooking/monitoring shellexecute/CreateThread etc ?
Create an executable yourself that just calls the original and passes all parameters on to it. Then move the original somewhere else and replace it with your exe. Your program can then log all calls to it, including all parameters.
Yes, there is - as you write Process Explorer is able to do it, and you could employ the same technique. But AFAIK there's no Delphi translation of the winternl.h file from the Platform SDK, so it is even more tedious and difficult. Also this is extremely version-specific, and there are chances it will break with the next Windows version. It's also not quite clear whether this works for 64 bit processes (from a 32 bit process).
If you really want to do it you will find the necessary information in this blog posting by Matt Pietrek, and in the CodeProject article "Read Environment Strings of Remote process".
If you do not plan to use it for closed source commercial programs then a look into the (GPL licensed) annotated version of the winternl.h file from the ReactOS project would probably also help.
It's a Win32 FAQ since 1992 : just read the PEB.
See on Win32 experts group.