So here is my issue. I'm trying to create function, which goes on straight away, but also have second exec output, which goes after let's say completing loop.
I tried to make this work with this: thread i googled.
However my issue is when i tried doing it with accepted answer provided i got this error:
E0434 a reference of type "TEnumAsByte<EMyEnum> &" (not const-qualified) cannot be initialized with a value of type "EMyEnum"
Going furthere below there is second answer, which work but it always goes off form last possible pin.In case I show below it always fire "FinishOutput". Is there any way i can force code to output from both pins i provide? Here is how it looks in my code:
.h file
UENUM(BlueprintType)
enum class EMyEnum : uint8
{
Output,
FinishOutput
};
UFUNCTION(BLueprintCallable, Category = "Test", Meta = (ExpandEnumAsExecs = "Branches"))
static void OutputTest(TEnumAsByte<EMyEnum>& Branches);
.cpp file
void UAudioController::OutputTest(TEnumAsByte<EMyEnum>& Branches)
{
Branches = EMyEnum::Output;
//some code to execute before second output
Branches = EMyEnum::FinishOutput;
}
I would make a Macro since it can have multiple Exec outputs. This is in blueprint, not code.
Related
I am implementing logging functionality in Unreal Engine 4.27 (in C++). A key part of my code is a function that is called once per game-tick. This function is responsible for iterating over an array of actors that I would like to log data for, checking whether a new log entry should be written at this point in time and calling the necessary functions to do that.
I am iterating over elements of a TArray of UStructs: LogObject->LoggingInfo = TArray<FActorLoggingInformation>. This array is defined as a UProperty of LogObject. In the loop I have to change the values of the elements so I want to work with the original items and "label" the current item as "ActorLoggingInfo". I have seen this done generally in cpp and also with TArrays. And yet my code does not work, there is no error message, but ActorLoggingInfo is undefined, thus the if-condition is never met.
This is the for-loop:
for (FActorLoggingInformation& ActorLoggingInfo : LogObject->LoggingInfo) {
if (ActorLoggingInfo.LogNextTick == true) {
ActorLoggingInfo.LogNextTick = false;
...
}
...
}
This is the definition of FActorLoggingInformation:
USTRUCT(BlueprintType)
struct FActorLoggingInformation
{
GENERATED_BODY()
public:
FActorLoggingInformation()
{
}
FActorLoggingInformation(int32 LogTimer, AActor* Actor, FString LogName)
{
this->LogTimer = LogTimer;
this->LogNextTick = false;
...
}
// Specifies Logging Frequency in ms
UPROPERTY(BlueprintReadOnly, VisibleAnywhere)
int32 LogTimer;
bool LogNextTick;
...
};
This is the debugger at run-time:
Additional Notes:
1. Something that consistently works for me is omitting the &, using:
for (FActorLoggingInformation ActorLoggingInfo : LogObject->LoggingInfo)
However, this is creating useless duplicates on a per-tick basis and complicates applying changes to the original objects from within in the for-loop, so it is not a viable option.
2. I have also tried auto& instead of FActorLoggingInformation& as used in the examples above, but I encountered the same issue, so I thought it would be best to be as explicit as possible.
I would be very thankful if you had any ideas how I can fix this :)
Thanks in advance!
Thanks to Avi Berger for helping me find my problem!
In fact, ActorLoggingInfo was actually never undefined and the code within the body of the if-clause was also executed (it just didn't do what it was intended to do).
When stepping through the code in the debugger it never showed the steps within the if-body and ActorLoggingInfo was shown as undefined so when no logs were written, I assumed it was something to do with that instead of my output function not working properly. So lesson learnt, do not blindly trust the debugger :)
Let me elaborate on the title:
I want to implement a system that would allow me to enable/disable/modify the general behavior of my program. Here are some examples:
I could switch off and on logging
I could change if my graphing program should use floating or pixel coordinates
I could change if my calculations should be based upon some method or some other method
I could enable/disable certain aspects like maybe a extension api
I could enable/disable some basic integrated profiler (if I had one)
These are some made-up examples.
Now I want to know what the most common solution for this sort of thing is.
I could imagine this working with some sort of singelton class that gets instanced globally or in some other globally available object. Another thing that would be possible would be just constexpr or other variables floating around in a namespace, again globally.
However doing something like that, globally, feels like bad practise.
second part of the question
This might sound like I cant decide what I want, but I want a way to modify all these switches/flags or whatever they are actually called in a single location, without tying any of my classes to it. I don't know if this is possible however.
Why don't I want to do that? Well I like to make my classes somewhat reusable and I don't like tying classes together, unless its required by the DRY principle and or inheritance. I basically couldn't get rid of the flags without modifying the possible hundreds of classes that used them.
What I have tried in the past
Having it all as compiler defines. This worked reasonably well, however I didnt like that I couldnt make it so if the flag file was gone there were some sort of default settings that would make the classes themselves still operational and changeable (through these default values)
Having it as a class and instancing it globally (system class). Worked ok, however I didnt like instancing anything globally. Also same problem as above
Instancing the system class locally and passing it to the classes on construction. This was kinda cool, since I could make multiple instruction sets. However at the same time that kinda ruined the point since it would lead to things that needed to have one flag set the same to have them set differently and therefore failing to properly work together. Also passing it on every construction was a pain.
A static class. This one worked ok for the longest time, however there is still the problem when there are missing dependencies.
Summary
Basically I am looking for a way to have a single "place" where I can mess with some values (bools, floats etc.) and that will change the behaviour of all classes using them for whatever, where said values either overwrite default values or get replaced by default values if said "place" isnt defined.
If a Singleton class does not work for you , maybe using a DI container may fit in your third approach? It may help with the construction and make the code more testable.
There are some DI frameworks for c++, like https://github.com/google/fruit/wiki or https://github.com/boost-experimental/di which you can use.
If you decide to use switch/flags, pay attention for "cyclometric complexity".
If you do not change the skeleton of your algorithm but only his behaviour according to the objets in parameter, have a look at "template design pattern". This method allow you to define a generic algorithm and specify particular step for a particular situation.
Here's an approach I found useful; I don't know if it's what you're looking for, but maybe it will give you some ideas.
First, I created a BehaviorFlags.h file that declares the following function:
// Returns true iff the given feature/behavior flag was specified for us to use
bool IsBehaviorFlagEnabled(const char * flagName);
The idea being that any code in any of your classes could call this function to find out if a particular behavior should be enabled or not. For example, you might put this code at the top of your ExtensionsAPI.cpp file:
#include "BehaviorFlags.h"
static const enableExtensionAPI = IsBehaviorFlagEnabled("enable_extensions_api");
[...]
void DoTheExtensionsAPIStuff()
{
if (enableExtensionsAPI == false) return;
[... otherwise do the extensions API stuff ...]
}
Note that the IsBehaviorFlagEnabled() call is only executed once at program startup, for best run-time efficiency; but you also have the option of calling IsBehaviorFlagEnabled() on every call to DoTheExtensionsAPIStuff(), if run-time efficiency is less important that being able to change your program's behavior without having to restart your program.
As far as how the IsBehaviorFlagEnabled() function itself is implemented, it looks something like this (simplified version for demonstration purposes):
bool IsBehaviorFlagEnabled(const char * fileName)
{
// Note: a real implementation would find the user's home directory
// using the proper API and not just rely on ~ to expand to the home-dir path
std::string filePath = "~/MyProgram_Settings/";
filePath += fileName;
FILE * fpIn = fopen(filePath.c_str(), "r"); // i.e. does the file exist?
bool ret = (fpIn != NULL);
fclose(fpIn);
return ret;
}
The idea being that if you want to change your program's behavior, you can do so by creating a file (or folder) in the ~/MyProgram_Settings directory with the appropriate name. E.g. if you want to enable your Extensions API, you could just do a
touch ~/MyProgram_Settings/enable_extensions_api
... and then re-start your program, and now IsBehaviorFlagEnabled("enable_extensions_api") returns true and so your Extensions API is enabled.
The benefits I see of doing it this way (as opposed to parsing a .ini file at startup or something like that) are:
There's no need to modify any "central header file" or "registry file" every time you add a new behavior-flag.
You don't have to put a ParseINIFile() function at the top of main() in order for your flags-functionality to work correctly.
You don't have to use a text editor or memorize a .ini syntax to change the program's behavior
In a pinch (e.g. no shell access) you can create/remove settings simply using the "New Folder" and "Delete" functionality of the desktop's window manager.
The settings are persistent across runs of the program (i.e. no need to specify the same command line arguments every time)
The settings are persistent across reboots of the computer
The flags can be easily modified by a script (via e.g. touch ~/MyProgram_Settings/blah or rm -f ~/MyProgram_Settings/blah) -- much easier than getting a shell script to correctly modify a .ini file
If you have code in multiple different .cpp files that needs to be controlled by the same flag-file, you can just call IsBehaviorFlagEnabled("that_file") from each of them; no need to have every call site refer to the same global boolean variable if you don't want them to.
Extra credit: If you're using a bug-tracker and therefore have bug/feature ticket numbers assigned to various issues, you can creep the elegance a little bit further by also adding a class like this one:
/** This class encapsulates a feature that can be selectively disabled/enabled by putting an
* "enable_behavior_xxxx" or "disable_behavior_xxxx" file into the ~/MyProgram_Settings folder.
*/
class ConditionalBehavior
{
public:
/** Constructor.
* #param bugNumber Bug-Tracker ID number associated with this bug/feature.
* #param defaultState If true, this beheavior will be enabled by default (i.e. if no corresponding
* file exists in ~/MyProgram_Settings). If false, it will be disabled by default.
* #param switchAtVersion If specified, this feature's default-enabled state will be inverted if
* GetMyProgramVersion() returns any version number greater than this.
*/
ConditionalBehavior(int bugNumber, bool defaultState, int switchAtVersion = -1)
{
if ((switchAtVersion >= 0)&&(GetMyProgramVersion() >= switchAtVersion)) _enabled = !_enabled;
std::string fn = defaultState ? "disable" : "enable";
fn += "_behavior_";
fn += to_string(bugNumber);
if ((IsBehaviorFlagEnabled(fn))
||(IsBehaviorFlagEnabled("enable_everything")))
{
_enabled = !_enabled;
printf("Note: %s Behavior #%i\n", _enabled?"Enabling":"Disabling", bugNumber);
}
}
/** Returns true iff this feature should be enabled. */
bool IsEnabled() const {return _enabled;}
private:
bool _enabled;
};
Then, in your ExtensionsAPI.cpp file, you might have something like this:
// Extensions API feature is tracker #4321; disabled by default for now
// but you can try it out via "touch ~/MyProgram_Settings/enable_feature_4321"
static const ConditionalBehavior _feature4321(4321, false);
// Also tracker #4222 is now enabled-by-default, but you can disable
// it manually via "touch ~/MyProgram_Settings/disable_feature_4222"
static const ConditionalBehavior _feature4222(4222, true);
[...]
void DoTheExtensionsAPIStuff()
{
if (_feature4321.IsEnabled() == false) return;
[... otherwise do the extensions API stuff ...]
}
... or if you know that you are planning to make your Extensions API enabled-by-default starting with version 4500 of your program, you can set it so that Extensions API will be enabled-by-default only if GetMyProgramVersion() returns 4500 or greater:
static ConditionalBehavior _feature4321(4321, false, 4500);
[...]
... also, if you wanted to get more elaborate, the API could be extended so that IsBehaviorFlagEnabled() can optionally return a string to the caller containing the contents of the file it found (if any), so that you could do shell commands like:
echo "opengl" > ~/MyProgram_Settings/graphics_renderer
... to tell your program to use OpenGL for its 3D graphics, or etc:
// In Renderer.cpp
std::string rendererType;
if (IsDebugFlagEnabled("graphics_renderer", &rendererType))
{
printf("The user wants me to use [%s] for rendering 3D graphics!\n", rendererType.c_str());
}
else printf("The user didn't specify what renderer to use.\n");
I have a function that is being used to update some information displayed on a GUI. The information should only be displayed for a short length of time (about 10 seconds).
The function being used to set what is displayed on the GUI is called repeatedly, and what is displayed is dependent on conditions within that function.
The issue that I'm having at the moment, is that there is some information being displayed that needs to change depending on how long it has been displayed for.
I tried creating a variable that was set to the system time at the beginning of the function, and then later in the function, had a condition that would change the value of the variable if the current system time was greater than the original system time + 10 seconds.
However, the problem with that was that since the function is being called repeatedly, the original system time is updated with every call/ iteration.
I found the following quesion on SO: How to run code inside a loop only once without external flag? and tried to implement what was suggested in the answer by Angew, so that the variable holding the original system time would only be set once within the loop. My code currently looks like this:
struct rnOnce{
template <typename T>
runOnce(T &&f){ f(); }
};
...
void updateHeader(){
...
static runOnce a([](){
timeWarningStarted = SimulationTime::Instance()->getSimulationTime();
});
...
But when I run my program, and attach to process in debug, the call to static runOnce a([](){... }); appears to be skipped- none of the breakpoints I've put on these lines are ever hit, even though the breakpoints on the lines just before and just after are.
Can anyone explain to me why this is? What am I doing wrong here?
EDIT
The desired behviour is that the timeWarningStarted variable is only given a value once, despite the fact that it is being set inside a function that is called several times. It is a global variable- and the function that is setting its value will be continuously called as that is the one that's used to update what is displayed on the GUI.
Effectively, I want timeWarnigStarted to be set to the current system time the first time that this code is executed, and then to retain its value for the duration of time that the program is running.
Before changing my code to what it is above, I had something similar to:
void updateHeader(){
...
timeWaringtarted = SimulationTime::Instance()->getSimulationTime();
...
}
But this was in issue because timeWarningStarted was being given the current system time every time this function was run (i.e. it was continuously being updated). So, later in the same function, when I wanted to check whether the warning had been displayed for 10 seconds, and if so, to stop it from being displayed, I was doing something like:
void updateHeader(){
...
timeWarningStarted = SimulationTime::Instance()->getSimulationTime();
...
currentSimulationTime = SimulationTime::Instance()->getSimulationTime();
if(currentSimulationTime <= (timeWarningStarted + 10)){
warningMessage = "";
}
...
}
But obviously, since both timeWarningStarted & currentSimulationTime will be given a new value every time the above code is run, they will have too close a value because they will be set at almost exactly the same time.
So, by setting timeWarningStarted inside runOnce, I was hoping that timeWarningStarted would only be given a value the first time that this code was run, and would retain that value for the duration of the simulation, but it appears that this section of code is now never run...
static runOnce a([](){
timeReplyFailWarningStarted = SESL::SimulationTime::Instance()->getSimulationTime(); // = 0;
});
To set timeWarningStarted the first time updateHeader() is called (not after, and not before), a simple technique is
void updateHeader() {
...
static bool warningHasStarted = false;
if (!warningHasStarted) {
timeWarningStarted = SimulationTime::Instance()->getSimulationTime();
warningHasStarted = true;
}
...
}
I am using this module hierarchy :
Node: {udpApp[0]<->udp<->networkLayer->wlan[0]} and wlan[0]: {CNPCBeacon<->mac<->radio}
I have given some initial parameter in the ini file for udpApp as :
**.host*.numUdpApps = 2
**.host*.udpApp[0].typename = "UDPBasicApp"
**.host*.udpApp[0].chooseDestAddrMode = "perBurst"
**.host*.udpApp[0].destAddresses = "gw1"
**.host*.udpApp[0].startTime = 1.32s
**.host*.udpApp[0].stopTime = 1.48s
But at run time I want to change the startTime and stopTime for udpAPP[0] through CNPCBeacon module. Hence I changed CNPCBeacon.cc as:-
cModule* parentmod = getParentModule();
cModule* grantParentmod = parentmod->getParentModule();
cModule* udpmod;
for (cSubModIterator iter(*grantParentmod); !iter.end(); iter++)
{
//EV<<"get the modulde "<< iter()->getFullName()<<endl;
if (strcmp(iter()->getFullName(), "udpApp[0]") == 0)
{
udpmod = iter();
break;
}
}
cPar& startTime = udpmod->par("startTime");
cPar& stopTime = udpmod->par("stopTime");
And I am successfully able to receive the values of startTime and stopTime. However I want to change these value in current module, which is resulting in an error by following code:
udpmod->par("startTime").setDoubleValue(4.2);
Can anybody please suggest me a way to change it at run time.
Declaring your parameter as volatile should solve your problem. But for future reference I'll provide further explanation below
Volatile vs. non-volatile:
Here it depends how you want to use this parameter. Mainly via the .ini file you have two types of parameters: volatile and non-volatile.
volatile parameters are read every time during your run. That woule be helpful if you want this parameter to be generated by a built-in function, for example, uniform(0,10) each time this volatile parameter will get a different value.
On the other hand non-volatile parameters are read just one, as they don't change from run to run.
Using the volatile type parameter does not give you full flexibility, in the sense that your parameter value will always fall with in a range predefined in the .ini
Dynamic Variable (parameter) Reassignment:
Instead what you could do is use a more robust approach, and re-define the variable which stores the value from that module parameter each time you have to do so.
For example in your case you could do the following:
varHoldingStartTime = par("startTime").doubleValue();
varHoldingStartTime = 4.2;
This way the actual value will change internally without reflecting to your run.
Parameter Studies:
Alternatively if you want this change of the parameter to be applied to multiple runs you could use the advanced built-in approach provided by OMNeT++ which allows you to perform Parameter Studies.
I have explained here how Parameter Studies work: https://stackoverflow.com/a/30572095/4786271 and also here how it can be achieved with constraints etc: https://stackoverflow.com/a/29622426/4786271
If none of the approaches suggested by me fit your case, answers to this question altogether might solve your problem: How to change configuration of network during simulation in OMNeT++?
EDIT: extending the answer to roughly explain handleParameterChange()
I have not used handleParameterChange() before as well, but from what can I see this function provides a watchdog functionality to the module which utilizes it.
To activate this functionality first the void handleParameterChange(const char *parameterName); has to be re-defined.
In essence what it seems to do is the following:
Assume we have two modules moduleA and moduleB and moduleB has parameter parB. moduleA changes the parB and when that happens, moduleB reacts to this change based on the behaviour defined in:
moduleB::handleParameterChange(parB);
The behaviour could be re-reading the original value for parB from the .ini etc.
I'm working on adding code complete via Clang to text editor to make it IDE.
The source code:
struct s {
int a;
float b;
};
void main() {
s var;
var.
The problem is that code complete for the position after dot returns nothing and if i add } at the end and retry code complete for the position after dot it shows the correct list.
I understand that the main function definition should be closed, but users frequently type chars one-by-one and don't want to close function first and then return back to variable and then get code complete. How can that be walked-around to avoid go back/return?
My idea was to get diagnostics and add } if i get according diagnostics, but it's unwished walk-around. Can Clang be smart enough to make it itself?