In NS2, is there any way to embed a C++ variable into the TCL script? For example, in TCL, set routing protocol like this, set opt(rt) XXX XXX could be a variable which is defined in C++ program, such as
if(CONDITION==1)
XXX = "FLOODING";
if(CONDITION==2)
XXX = "AODV";
...
The easiest way is to use Tcl_LinkVar to couple the char* variable in C++ (std::string not supported) to Tcl. Like that, all you have to do is change the C++ variable and call Tcl_UpdateLinkedVar to allow Tcl to notice that the variable has changed. You do not need to use Tcl_UpdateLinkedVar if you never have any traces set on the variable, but they're actually quite a common mechanism so doing the call is advised. Be aware that Tcl_UpdateLinkedVar is a reentrant call to the Tcl interpreter; some care should be taken to ensure that any traces you run do not trigger a loop back into your code…
// Setup (done once)...
Tcl_LinkVar(interp, "XXX", &XXX, TCL_LINK_STRING|TCL_LINK_READ_ONLY);
// Your code ...
if(CONDITION==1)
XXX = "FLOODING";
if(CONDITION==2)
XXX = "AODV";
// Notify Tcl ...
Tcl_UpdateLinkedVar(interp, "XXX");
If you want the setting of the Tcl variable XXX to change the C++ variable XXX, you need to take extra care. Drop the use of the TCL_LINK_READ_ONLY and ensure that you always use ckalloc to allocate memory for the strings in XXX (because Tcl will use the matched ckfree to dispose of the old one when setting the C++ variable).
Related
I'm working on a project, where I wanted to access a sound file from C:/Windows/media, but to keep it more general, I want to use some environment variable from the user's system.
This code works At the moment
soundURL = QUrl::fromUserInput(soundFilename,
QStringLiteral("C:/Windows/media"),
QUrl::AssumeLocalFile);
I have tried the below code, doesn't work
soundURL = QUrl::fromUserInput(soundFilename,
QStringLiteral((%%WINDIR%%)+"/media"),
QUrl::AssumeLocalFile);
How can I make use of %WINDIR% to make the path simpler and more general?
Qt5 exposes several functions to retrieve the value stored in an environment variable, namely qgetenv and qEnvironmentVariable.
As you seem to target Windows, the safer is to use QString qEnvironmentVariable(const char *varName)
QString winDirPath = qEnvironmentVariable("WINDIR");
if (!winDirPath.isNull()) {
// the environment variable WINDIR exists and has been retrieved
} else {
// the environment variable does not exists in this system
}
string path(getenv("WINDIR"));
will put %WINDIR% in a std::string. I would expect you can do the same with Qt types.
You're probably better off using Qt Standard Paths http://doc.qt.io/qt-5/qstandardpaths.html. Messing with %WINDIR% is a bit dangerous.
I'm currently writing some kind of a "skeleton" for tests to be performed using Lauterbach scripts.
In this skeleton I want to have a part in which all test specific definitions shall be done, e.g. functions to set breaks on, variables to be altered etc. This part shall be just near the top of the script file, so that other users do not have to go through the complete script file, changing values here and there.
Some of the variables that'll be used are defined function-local within the C-code to be tested. So, these become available to the Lauterbach script only once the scope of that function has been entered - which is deeply within the skeleton script code.
Is there a way to define a macro for these variables just way before the scope has been entered?
Let's give some example structure:
LOCAL &funcToTest // the function we want to test
LOCAL &varToBeSet // a variable within the function we want to alter
LOCAL &valueToBeSet // the value we want to set &varToBeSet to
... // some more definitions here
&funcToTest=someFunc
&varToBeSet=status
&valueToBeSet=1
... // some test code following here that sets up log files, screen areas
... // start the program to be tested etc.
IF (Register(PC)==ADDRESS.OFFSET(&funcToTest))
(
// OK - we've hit the breakpoint inside the function to test
... // Run to some point where we can set the local variable
Var.Set &varToBeSet=&valueToBeSet
... // Go on with the program and see what happens - this will be logged
)
The problem is that Lauterbach complains at the line &varToBeSet=status
with Symbol not found in this context - which is correct, because it is a local variable.
Looking at the symbols via View->Symbols->SymbolsTreeView (or by giving the command Symbol.List.Tree) I can find the symbol (in this particular case found under the node some_module.some_function.status). Clicking on it gives the information in the TRACE32 status status line \\some_app\some_module\some_func\status with type (auto STATUS), scope local, location stack.
Changing my script to read &varToBeSet=\\some_app\some_module\some_func\status instead of &varToBeSet=status, however, does not help much. In this case Lauterbach complains with no access to that symbol.
Is there a way, I can delay evaluation of the macro to some point where it is actually used instead of having it evaluated when it is defined?
Use quotes:
&varToBeSet="\\some_app\some_module\some_func\status"
Is it possible to execute C++ code from within Progress ABL?
Specifically, I am looking to use the function SHGetKnownFolderPath (documentation here) to determine the location of the "Documents" folder on a Windows 7 machine that has the documents folder redirected to another location.
Or, is there an alternative way to determine this information without resorting to checking a registry key?
You can call external shared libraries and DLLs.
http://documentation.progress.com/output/OpenEdge113/pdfs/dvpin/dvpin.pdf
Section 3 "External Interfaces" is what you are looking for.
This http://dbappraise.com/ppt/shlib.pptx might also be helpful.
C++ is often problematic due to the way it names things. You might be better off building a "shim" using plain old C to bridge between OpenEdge and C++
Callling Windows system functions is usually easy though. Something like:
procedure SHGetKnownFolderPath external "pathToLibrary":
define parameter a as someType.
define parameter b as someType.
define return parameter x as someType.
end.
Check the "Programming Interfaces" document, "External Program Interfaces" section.
Also, some versions of ABL also support direct .NET calls as an option.
I was able to get this working in 10.2B after consulting some sources:
The C# solution, for a working example: https://stackoverflow.com/a/21953690/763102
Win32 OpenEdge samples, for translation examples: http://www.oehive.org/book/export/html/385.html
The difficult part for SHGetKnownFolderPath is the rfid parameter which needs to be passed by reference. C# has the annotation [System.Runtime.InteropServices.MarshalAs(UnmanagedType.LPStruct)] or the ref keyword. I couldn't figure out how to pass a reference of System.Guid due to Progress OpenEdge's limitations of external procedure parameter datatypes, so I performed a bytewise copy of a .NET Guid and passed that via MEMPTR. I apologize for leaning so heavily on .NET here.
Here is a working example that gets the provided known folder GUID, plus usage to get the Documents folder:
PROCEDURE SHGetKnownFolderPath EXTERNAL "shell32.dll":
DEFINE INPUT PARAMETER rfid AS MEMPTR.
DEFINE INPUT PARAMETER dwFlags AS UNSIGNED-LONG.
DEFINE INPUT PARAMETER hToken AS LONG.
DEFINE OUTPUT PARAMETER ppszPath AS LONG.
DEFINE RETURN PARAMETER result AS LONG.
END PROCEDURE.
FUNCTION prepareGuidPointer RETURNS MEMPTR(
pGuid AS System.Guid):
DEFINE VARIABLE lGuidBytes AS INTEGER EXTENT.
ASSIGN lGuidBytes = pGuid:ToByteArray().
DEFINE VARIABLE lGuidPointer AS MEMPTR NO-UNDO.
SET-SIZE(lGuidPointer) = EXTENT(lGuidBytes).
DEFINE VARIABLE ii AS INTEGER NO-UNDO.
DO ii = 1 TO EXTENT(lGuidBytes):
PUT-BYTE(lGuidPointer, ii) = lGuidBytes[ii].
END.
RETURN lGuidPointer.
END FUNCTION.
FUNCTION deallocatePointer RETURNS INT64(
pPointer AS MEMPTR):
SET-SIZE(pPointer) = 0.
RETURN GET-SIZE(pPointer).
END FUNCTION.
FUNCTION GetKnownFolderPath RETURNS CHARACTER(
pGuidString AS CHARACTER):
DEFINE VARIABLE lDontVerifyFolderFlag AS INT64 NO-UNDO
INITIAL 16384. /* 0x4000 */
DEFINE VARIABLE lUseDefaultUser AS INTEGER NO-UNDO
INITIAL 0.
DEFINE VARIABLE lGuidPointer AS MEMPTR NO-UNDO.
ASSIGN lGuidPointer = prepareGuidPointer( NEW System.Guid(pGuidString) ).
DEFINE VARIABLE lResult AS INTEGER NO-UNDO.
DEFINE VARIABLE lPathResponse AS INTEGER NO-UNDO.
RUN SHGetKnownFolderPath(
INPUT lGuidPointer,
INPUT lDontVerifyFolderFlag,
INPUT lUseDefaultUser,
OUTPUT lPathResponse,
OUTPUT lResult).
deallocatePointer(lGuidPointer).
IF lResult GE 0 THEN
DO:
DEFINE VARIABLE lStringPath AS CHARACTER NO-UNDO.
DEFINE VARIABLE lPathPointer AS System.IntPtr NO-UNDO.
ASSIGN lPathPointer = NEW System.IntPtr(lPathResponse).
ASSIGN lStringPath =
System.Runtime.InteropServices.Marshal:PtrToStringUni(lPathPointer).
System.Runtime.InteropServices.Marshal:FreeCoTaskMem(lPathPointer).
RETURN lStringPath.
END.
ELSE
UNDO, THROW NEW System.Runtime.InteropServices.ExternalException(
"Unable to retrieve the known folder path. It may not be available on this system.",
lResult).
END FUNCTION.
DEFINE VARIABLE lDocumentsGuidString AS CHARACTER NO-UNDO
INITIAL "~{FDD39AD0-238F-46AF-ADB4-6C85480369C7}".
MESSAGE GetKnownFolderPath(lDocumentsGuidString)
VIEW-AS ALERT-BOX.
The following code works:
<cfoutput>#$.currentURL()#</cfoutput>
However, within a function, "$" is not available.
<cfscript>
function myTest() {
return $.currentURL();
}
</cfscript>
Does anyone know what actually is the equivalent of $ within a function?
Likewise, #pluginConfig.getDirectory()# works when used directly in cfoutput. However, within a cfscript function, it reports "unknown variable pluginConfig."
Thank you for advance for guiding me in the right direction.
When writing code outside the Mura Event Scope (like you do with that function), you have to obtain an instance of the Mura Scope ($) yourself. This can be done using the following code:
$ = application.serviceFactory.getBean('$');
Next you'll have to initialise the instance using an event object, a struct with value pairs or a 'siteID':
$.init(event);
$.init(myStruct);
$.init(siteID);
The same counts for the pluginConfig, this you can abtain via the Mura Scope. You'll have to pass the pluginID, moduleID, name or package of the plugin:
$.getPlugin(pluginID);
$.getPlugin(moduleID);
$.getPlugin(name);
$.getPlugin(package);
An other option you have is to pass the Mura Scope and the pluginConfig as arguments to the function. When writing a small plugin, this might be the easier way. But when writting medium or large plugins, it will get a bit messy when you're passing along these objects all the time.
The $ is used as a special framework variable in some CF frameworks (like Mura). You will need to figure out the framework context (if any) your code is executing in
My current problem is that I have several enemies share the same A.I. script, and one other object that does something different. The function in the script is called AILogic. I want these enemies to move independently, but this is proving to be an issue. Here is what I've tried.
1) Calling dofile in the enemy's constructor, and then calling its script function in its Update function which happens in every game loop. The problem with this is that Lua just uses the script of the last enemy constructed, so all of the enemies are running the same script in the Update function. Thus, the object I described above that doesn't use the same script for it's A.I. is using the other enemies' script.
2) Calling dofile in the Update function, and then calling its script function immediately after. The problem with this is that dofile is called in every object's update function, so after the AILogic function runs and data for that script is updated, the whole thing just gets reset when dofile is called again for another enemy. My biggest question here is whether there is some way to retain the values in the script, even when I switch to running a different one.
I've read about function environments in Lua, but I'm not quite sure how to implement them correctly. Is this the right direction? Any advice is appreciated, thanks.
Edit: I've also considered creating a separate place to store that data rather than doing it in the Lua script.
Edit2: Added some sample code. (Just a test to get the functionality working).
-- Slime's Script
local count = 0;
function AILogic( Slime )
--Make the slime move in circles(err a square)
if count < 4 then
Slime:MoveDir( 0 );
elseif count < 8 then
Slime:MoveDir( 2 );
elseif count < 12 then
Slime:MoveDir( 1 );
elseif count < 16 then
Slime:MoveDir( 3 );
else
count = 0;
end
count = count + 1;
end
The lua interpreter runs each line as its own chunk which means that locals have line scope, so the example code can't be run as-is. It either needs to be run all at once (no line breaks), without locals, or run in a do ... end block.
As to the question in the OP. If you want to share the exact same function (that is the same function at runtime) then the function needs to take the data as arguments. If, however, you are ok with using the same code but different (runtime) functions than you can use closures to hold the local/individual data.
local function make_counter()
local count = 0
return function ()
local c = count
count = count + 1
return c
end
end
c1 = make_counter()
c2 = make_counter()
c3 = make_counter()
print(c1())
print(c1())
print(c1())
print(c1())
print(c2())
print(c3())
print(c2())
print(c3())
print(c2())
print(c3())
Alternatively, you could play with the environment of the function each time it is called, but that will only work correctly for some cases (depends on what the internals of the function are).
The canonical reference for this is link text. Explaining this briefly we'll work off the following code from the site:
a = 1
local newgt = {} -- create new environment
setmetatable(newgt, {__index = _G})
setfenv(1, newgt) -- set it
The first line sets up the (global) variable "a". You can view this as setting default values for your code. (Keep in mind that in Lua all variables are global unless you declare them with "local".)
The next line creates a table that will be your new environment. It is local to the function/chunk you're executing in so it won't be trashed by anything else that runs now or later.
The third line is the beginnings of the magic. To understand it you're going to have to understand metamethods In essence, however, you're using Lua's metamagic to ensure that any global names that aren't defined in your soon-to-be function environment get resolved in the context of your old global environment. Basically it means if you use a name that's not in your function environment, Lua will automagically hunt in the global environment you used to have to find the name. (In a word: inheritance.)
The fourth line is where you get what you're looking for. Setfenv(1,...) means that this changes the environment for your current function. (You could use 2 for the calling function, 3 for the calling function's caller, etc. on up the line.) The second parameter is the table you just set up, complete with inheritance of the old behaviour. Your function is now executing in a new global environment. It has all the names and values of the old environment handy (including functions and that global variable "a" you put in). If, however, you WRITE to a name it will not overwrite the global state. It will overwrite your local copy of it.
Consider the following subsequent code:
a = 10
b = 20
What you have done now is made your function environment table look like this:
{a = 10, b=20}
Your "global" environment, in short, contains two variables only: a (value 10) and b (value 20). When you access "a" later you'll get your local copy with 10 -- the old global value stored in your metatable is shadowed now and is still set to 1 -- and if you access "b" you'll get 20, despite the original global state likely not even having a variable "b" to access. And you'll still be able to access all the functions, etc. you've defined before this point as well.
Edited to add test code to debug OP's problem.
I put the following code into "junk.lua":
a = 1
local newgt = {}
setmetatable(newgt, {__index = _G})
setfenv(1, newgt)
print(a)
a = 10
print(a)
print(newgt)
The output of it is as follows:
$ lua junk.lua
1
10
table: 0x976d040
This is using Lua 5.1.4. What is the output you're seeing?