How can I get a callback within my application when an executable (such as pbs, cp, etc) launches and then exits? This would need to work only knowing the path to the executable.
You could move the original executable aside, and replace it with a wrapper that runs the original, reporting when it runs and exits.
You could look at the accton and lastcomm commands, which record the start and exit of every process on the system.
You could look into using dtrace, which can definitely do what you're asking but it's rather complicated to use. You'd probably have to do a fair amount of learning to do this. I don't know much about writing dtrace scripts, but I'd probably start with execsnoop as my model.
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My Labview Program works like a charm, until I look at the Block Diagram. No changes are made. I do not Save. Just Ctrl+E and then Ctrl+R.
Now it does not work properly. Only a Restart of Labview fixes the problem.
My Program controls two Scanner arrays for Laser Cutting simultaneously. To force parallel working, I use the Error handler and loops that wait for a signal from the Scanner. But suddenly some loops run more often than they should.
What does majorly happen in Labview when I open the Block diagram that messes with my code?
Edit:
Its hard to tell what is happening without violating my non-disclosure agreement.
I'm controlling two independent mirror-Arrays for Laser Cutting. While one is running one Cutting-Job, the other is supposed to run the other Jobs. Just very fast. When the first is finished they meet at the same position and run the same geometry at the same slow speed. The jobs are provided as *.XML and stored as .net Objects. The device only runs the most recent job and overwrites it when getting a new one.
I can check if a job is still running. While this is true I run a while loop for the other jobs. Now this loop runs a few times too often and even ignores WAIT-blocks to a degree. Also it skips the part where it reads the XML job file, changes the speed part back to fast again and saves it. It only runs one time fast.
#Joe: No it does not. It only runs once well. afterwards it does not.
Youtube links
The way it is supposed to move
The wrong way
There is exactly one thing I can think of that changes solely by opening the block diagram.
When the block diagram opens, any commented-out or unreachable-code-compiler-eliminated sections of code will load their subVIs. If one of those commented out sections of code were somehow interfere with your running code, you might have an issue.
There are only two ways I know of for that to interfere... both of them are fairly improbable.
a) You have some sort of "check for all VIs in memory" or "check for all types in memory" that you're using as a plug-in system. When the commented-out sections load, that would change the VIs in memory. Such systems are not uncommon when parsing XML, so maybe.
b) You are using Run VI method for some dynamically invoked VI to execute as a top-level VI, but by loading the diagram, it discovers that it is a subVI of your current program. A VI cannot simultaneously be top-level and a subVI, so the call to Run VI returns an error.
That's it. I can't think of anything else. Both ideas seem unlikely, but given your claim and a lack of a block diagram, I figured I'd post it as a hypothesis.
In the improbable case someone has a similar problem. The problem was a xml file that was read during run time. Sometimes multiple instances tried to access it and this produced the error.
Quick point to check: are Debug and "retain data in wires" disabled? While it may not change the computations, but it may certainly change the timing of very tight loops, and that was one of the unexpected program behaviors, OP was referring to.
For example, when we call write(...) in program in minix. Does a new process is created(like with fork()) or is it done within current process?
Is it efficient to make a lot of syscalls?
Process creation is strictly fork's / exec's job. What kind of process could a system call like write possibly spawn?
Now, Minix is a microkernel, meaning that things like file systems run in userland processes. Writing to a file could therefore possibly spawn a new process somewhere else, but that depends on your file system driver. I haven't paid attention to the MinixFS driver so far, so I can't tell you whether that happens -- but it's not very likely, process creation still being relatively expensive.
It's almost never efficient to make a lot of syscalls (context switches being involved). However, "performant", "efficient" and "a lot" are all very relative things, so I can't tell you something you probably don't know already.
Is there possibility to show what's going on under specified process in Linux?
For example, i run SQL query -> select evil_function();
and notice that process under Linux uses all cpu.
So is there something with what I can see whats going on under this process?
What I want is to see what queries is running under this process.
Thanks!
strace will tell you what system calls the process is making.
To see what called routines are taking the most CPU, you need to run a profiling tool, and make sure the executable of the process you in compiled correctly (sometimes it needs to be instrumented during compilation for profiling, sometimes it just needs to be compiled with debug symbols, or not stripped of them after compilation).
You might want to look at oprofile, valgrind, gprof and for starters on free tools - there are also commercial products available.
Here are a few links:
http://www.pixelbeat.org/programming/profiling/
http://en.wikipedia.org/wiki/List_of_performance_analysis_tools
You are mixing a whole bunch of things.
If you are talking about MySQL do:
show processlist;
For info specifically about linux processes, you can strace the process to get a list of system function that it calls. Unless you are experienced with linux this will be useless to you.
If the process is paused then you can find out what function it is stopped on, but that's probably not what you want, since you say the process is running.
There are also various tools that can give you info on what parts of the disk the process is reading, and how much memory it's allocating.
And finally you can use gdb to break into the process and single step your way through it to see exactly what it's doing. This will also likely be useless to you since an SQL server does a LOT of things - far to many to understand by this method.
is there any way to use html anchor tag in a gml file..I want to create a hyperlink to location/point in a gml file.
how can i do so???
thanks in advance..
This is a little known GML technique that GREATLY increases the power of Game Maker, and is well worth learning, but as a note, it does NOT work in Studio, because of the countless new restrictions on commands. Go back to GM8.1 (I only ever use that now), and you should have no problem making use of this technique.
The technique is to write a program in another language through GML (batch, vbs, etc, or in this case, HTLM), execute it through GML, then delete the program.
Quite simply, use the file_text commands to create a file with the correct content and extension, execute it with execute_program, and then delete it with file_delete.
Specifically for this script:
argument0 is the link, including the protocol.
argument1 is the anchor, minus the # (that's handled for you).
argument2 is the full browser path.
argument3 is important. This is the time in milliseconds the program will wait before deleting the temporary link file.
(The execute_program command, even when told to wait for the program to complete, continues as soon as the temp file is loaded. If external, the redirect takes some time depending on your connection, so deleting the temporary file halfway through will cause it to fail. 10 milliseconds worked fine for me. The program will hang for this time in this setup, but if you would like to set up an alarm based system to stop it from hanging, that wouldn't be too hard.)
In other uses of this technique without the use of the internet (I use small batch and vbs files a lot), the "hang time" (pun not intended) is usually not necessary.
In addition, the browser location will need to be changed for each different computer
file=file_text_open_write(temp_directory+"\tempLink.html")
file_text_write_string(file,'<!DOCTYPE html>')
file_text_writeln(file)
file_text_write_string(file,'<html>')
file_text_writeln(file)
file_text_write_string(file,'<body onload="')
file_text_write_string(file,"location.href='")
file_text_write_string(file,argument0+"#"+argument1+"';")
file_text_write_string(file,'">')
file_text_writeln(file)
file_text_write_string(file,'</body>')
file_text_writeln(file)
file_text_write_string(file,'</html>')
file_text_close(file)
execute_program(argument2,temp_directory+"\tempLink.html",true)
sleep(argument3)
file_delete(temp_directory+"\tempLink.html")
Sorry I wish It was possible but it's not unless you want to spend a lot of time with dll's. BUT you can create a Script and reuse it everywhere in your code...
script0(argument0,argument1...)
Whether this is possible I don't know, but it would mighty useful!
I have a process that fails periodically (running in Windows 2000). I then have just one chance to react to it before having to restart it and painfully wait for it to fail again. I didn't write the process so don't have the source to debug. The failure is seemingly random.
With a snapshot of the process I could repeatedly and quickly test reactions to the failure.
I had thought of running inside a VM but this isn't possible in this instance.
EDIT:
#Jon Cage asked:
When you say a snapshot, you mean capturing a process when it's about to fail (including memory, program state etc. etc.) ...and then replaying it's final few seconds repeatedly to see what effect it has on some other component?
This is exactly what I mean!
I think minidump is what you are looking for.
You can also used Userdump:
The User Mode Process Dumper
(userdump) dumps any running Win32
processes memory image (including
system processes such as csrss.exe,
winlogon.exe, services.exe, etc) on
the fly, without attaching a debugger,
or terminating target processes.
Generated dump file can be analyzed or
debugged by using the standard
debugging tools.
This article shows you how to use it.
My best bet is to start the process in a debugger (OllyDbg being my preferred tool).
The process will pause on an exception, and you can try to figure out what happened shortly before that.
This needs some understanding of assembler and does not allow to create a snapshot of the process for later analysis. You would need to write your own debugger for that - it should be theoretically possible.