I tried out some of the samples coming along with ZeroBraneStudio.
spirograph-samples are working fine. May be there should be also a wait() statement at the end of the livecoding-samples and the fractal-samples. Otherwise the graphic window disappears at the end of execution. For
fractal-samples: zplane.lua I get an error:
Zoom: {1}
Cent: {0,0}
Area: {-2,2,-2,2}
/Applications/ZeroBraneStudio.app/Contents/ZeroBraneStudio/bin/lua.app
/Contents/MacOS/lua: ./fractal.lua:123: attempt to index local 'C' (a nil value)
stack traceback:
./fractal.lua:123: in function 'Draw'
..ts/ZeroBraneStudio/myprograms/fractal-samples/zplane.lua:103: in main chunk
[C]: at 0x00001c80
In my version of fractal.lua there is no reference to C variable on line 123. I'd try a newer version, as I don't see any issue with the execution of zplane.lua with the current version of fractal.lua.
Related
I'm getting the android logcat message "A resource failed to call close". I've tracked it down to where that message gets generated. Here's the code:
Properties defaultProperties = new Properties();
URL propURL = Util.class.getClassLoader().getResource(DEFAULT_PROPERTIES_FILE);
if (propURL != null)
{
InputStream is = null;
try
{
// Load properties from URL.
is = propURL.openConnection().getInputStream();
defaultProperties.load(is);
is.close();
}
catch (Exception ex)
{
The message is generated on the call to "defaultProperties.load(is)".
I put a breakpoint on that line, and when I step over that line, the warning message is generated. I'm not the author of the code but that line gets executed at least two times and its the second time when that line gets called when the warning gets generated. I just don't see how under any circumstances that a resource failed to close would be generated on that line. I'm at a lost to explain how or why that error message would be generated there. Any ideas?
After thinking about this, I've come to the conclusion that the problem doesn't have anything to do with the line "defaultProperties.load(is)" causing the warning. Although the message is always generated the second time that line is called, my current thought is that the problem is happening elsewhere but when this line gets called it's probably yielding to some other VM related thread time to process, and that process is detecting that some resource failed to close. I'm concluding that the problem is related to something altogether different and calling that line is the time when the problem surfaces, but it's not what's causing the problem.
I get a window ID from the command line, and create an SDL window with it:
Window window_id = from_cli(); // e.g. 0x34000c8
w = SDL_CreateWindowFrom((void*) (Window) window_id);
When my program finishes I try to clean up:
SDL_DestroyWindow(w);
And that is when I got an X11 error:
X Error of failed request: BadWindow (invalid Window parameter)
Major opcode of failed request: 3 (X_GetWindowAttributes)
Resource id in failed request: 0x34000c8
Serial number of failed request: 255
Current serial number in output stream: 256
Obviously, the caller of my program - which I cannot change - has already destroyed the X window I was using.
How should I handle this situation?
SDL_DestroyWindow() can be omitted if the SDL window was created with SDL_CreateWindowFrom()
go for SDL_SysWMinfo, pick up x11.display, create my own X11 error handler, and filter errors for window_id?
Looking at the SDL2-2.0.9 source code, it seems that SDL already sets an error handler, which calls the previous error handler, which is the default one that terminates the program on error. (src/video/x11/SDL_x11video.c::X11_SafetyNetErrHandler())
Internally SDL will override this error handler temporarily, when doing its own stuff. (src/video/x11/SDL_x11video.c::X11_CheckWindowManager())
Thus, I guess 2) is the correct way to go.
EDIT:
When omitting SDL_DestroyWindow(), SDL_Quit() will fail with the same X error.
I also realized that SDL may not anticipate a failed X call, so ignoring the error may not be a good idea, after all.
EDIT2:
I just realized that SetErrorHandler() does not require a display.
Adding an X error handler that ignores X errors regarding this particular X window seems to work, not sure if it creates new problems unseen.
Is there preferred way to handle this problem?
Version:
SDL2-2.0.9
In the software called Roblox studio I need help making a script that whenever an error happens in game, it would print out the error again using the normal print function something like this example here:
Local error = —-whatever the error that happened was
Print(error) —- so it just simply prints it back out
Roblox provides a few different ways to keep track of when errors are thrown in your Scripts and LocalScripts.
If you want to observe errors locally in a script, and you know a specific chunk of code may throw errors, you can use pcall() as a try-catch block.
local success, result = pcall(function()
error("this is a test error message")
end)
if not success then
print("An error was thrown!")
print(result) --"this is a test error message"
end
If you want to observe errors across all of your scripts, you can attach a callback to the ScriptContext.Error signal. This signal fires any time any error is thrown. It provides information about the error, including the message, the callstack, and a reference to the script that threw the error.
Warning : ScriptContext.Error only fires in the context of the script that registers it. A Script will only observe errors thrown in server scripts, and registering in a LocalScript will only observe errors thrown on the client.
local ScriptContext = game:GetService("ScriptContext")
ScriptContext.Error:Connect( function(message, stack, context)
print("An error was thrown!")
print("Message : ", message)
print("Stack : ", stack)
print("Context :", context:GetFullName())
end)
Similarly, if you only care about the error messages themselves, you can also observe them being printed out to the Output window using the LogService.MessageOut signal. This signal fires any time anything is logged to Output. This includes messages, warnings, and errors.
local LogService = game:GetService("LogService")
LogService.MessageOut:Connect( function(message, messageType)
if messageType == Enum.MessageType.MessageError then
print("An error was thrown!")
print(message)
end
end)
Use the stderr stream from io library to print debug messages.
-- Define debug function based in print
function debug(...) io.stderr:write(table.concat({...}, '\9') .. '\n') end
-- Debug acts as a regular "print()", but it writes to stderr instead
debug('[filename.lua]', 'debug')
Use "error()" function to print errors.
if true then
error("It should not be true!")
end
If you want to catch errors from a function, use xpcall()
-- Define debug
function debug(...) io.stderr:write(table.concat({...}, '\9') .. '\n') end
xpcall(
function()
local b = {}
-- This will throw an error because you cant index nil values
print(a.b)
end,
function(err)
debug('[xpcall]', err)
end
)
xpcall() wont stop the execution in case of error, so you only need to encapsulate your code in it if you want to catch any unexpected errors at runtime.
Is it possible to throw a Lua error from a function to be handled by the script calling the function?
For example the following will throw an error at indicated comment
local function aSimpleFunction(...)
string.format(...) -- Error is indicated to be here
end
aSimpleFunction("An example function: %i",nil)
But what I would rather do is catch the error and throw out a custom error by the function caller
local function aSimpleFunction(...)
if pcall(function(...)
string.format(...)
end) == false then
-- I want to throw a custom error to whatever is making the call to this function
end
end
aSimpleFunction("An example function: %i",nil) -- Want the error to start unwinding here
The intention being that in my actual use cases my functions would be more complicated and I would like to provide more meaningful error messages
The stack level of an error can be specified when throwing a new error
error("Error Message") -- Throws at the current stack
error("Error Message",2) -- Throws to the caller
error("Error Message",3) -- Throws to the caller after that
Usually, error adds some information about the error position at the beginning of the message. The level argument specifies how to get the error position. With level 1 (the default), the error position is where the error function was called. Level 2 points the error to where the function that called error was called; and so on. Passing a level 0 avoids the addition of error position information to the message.
Using the example given in the question
local function aSimpleFunction(...)
if pcall(function(...)
string.format(...)
end) == false then
error("Function cannot format text",2)
end
end
aSimpleFunction("An example function: %i",nil) --Error appears here
Use the error function.
error("something went wrong!")
Catching an error is as simple as using pcall
My_Error()
--Error Somehow
end
local success,err = pcall(My_Error)
if not success then
error(err)
end
Undoubtedly you're asking how this works. Well pcall runs a function in a protected thread (protected-call) and returns a bool, if it ran successfully, and a value (what it returned/the error).
Also don't think this means arguments to the function are impossible, simply pass them to pcall as well:
My_Error(x)
print(x)
--Error Somehow
end
local success,err = pcall(My_Error, "hi")
if not success then
error(err)
end
For more error handling control, see http://www.lua.org/manual/5.3/manual.html#2.3 and http://wiki.roblox.com/index.php?title=Function_dump/Basic_functions#xpcall
checkmodel([Some Model]) opens the GUI "Dymola Messages", tab "Translation" and displays Errors, Warnings, and Messages.
Does anyone know how to write these infos to a logfile or get them as kind of return value of checkModel(). All I've found in the documentation was, that checkModel() only returns a success-boolean. Are these infos saved temporarily somewhere?
Note, that I only want to apply checkModel() but not actually translating the code.
I finally found a solution at least for Dymola 2016 and newer, so if someone is interested - here it is (it is not very user-friendly, but it works):
The key-command is getLastError() which not only returns the last error (as one could think...), but all errors that are detected by checkModel() as well as the overall statistics.
All informations are sampled in one string, in which the last lines looks like:
"[...]
Local classes checked, checking <[Some Path]>
ERROR: 2 errors were found
WARNING: 13 warnings were issued
= false
"
Following operations will return the number of actual errors (for warnings it is more or less the same):
b = checkmodel([Some Model])
s = getLastError()
ind1 = Modelica.Utilities.Strings.findLast(s,"ERROR:")
ind2 = Modelica.Utilities.Strings.findLast(s," errors were found")
nErrors = Modelica.Utilities.Strings.substring(s,ind1+6,ind2) //6 = len(ERROR:)
nErrors = Modelica.Utilities.Strings.replace(nErrors," ","")
nErrors
= "2"
Note:
I used findLast as I know, that the lines of interest are at the very end of the string. So this is significantly faster than using find
This only works, if the line "ERROR: ...." actually exists. Otherwise, the substring call will throw an error.
Of course this could be done in less lines, but maybe this version is easier to read.
NOTE: This will only works with Dymola 2016 and newer. The return-string of getLastError is of a different structure in Dymola 2015 and older.
The following should handle it:
clearlog(); // To start fresh
Advanced.TranslationInCommandLog=true;
checkModel(...);
savelog(...);
This is mentioned in the Dymola User Manual Volume 1, section "Parameter studies by running Dymola a number of time in “batch mode”" on pg 630 or so.