I have a header file with all the enums listed (#ifndef #define #endif construct has been used to avoid multiple inclusion of the file) that I use in multiple cpp files in my application.One of the enums in the files is
enum StatusSubsystem {ENABLED,INCORRECT_FRAME,INVALID_DATA,DISABLED};
There are functions in the application delcared as
ShowStatus(const StatusSubsystem&);
Earlier in the application when I made calls to the above function like
ShowStatus(INCORRECT_FRAME);
my application used to compile perfectly. But after some code was added The compilation halts giving the following error:
File.cpp:71: error: invalid conversion from `int' to `StatusSubsystem'
File.cpp:71: error: initializing argument 1 of `void Class::ShowStatus(const StatusSubsystem&)
I checked the code for any conflicting enums in the new code and it looked fine.
My Question is what is wrong with the function call that compiler shows as erroneous?
For your reference the function definition is:
void Class::ShowStatus(const StatusSubsystem& eStatus)
{
QPalette palette;
mStatus=eStatus;//store current Communication status of system
if(eStatus==DISABLED)
{
//select red color for label, if it is to be shown disabled
palette.setColor(QPalette::Window,QColor(Qt::red));
mLabel->setText("SYSTEM");
}
else if(eStatus==ENABLED)
{
//select green color for label,if it is to be shown enabled
palette.setColor(QPalette::Window,QColor(Qt::green));
mLabel->setText("SYSTEM");
}
else if(eStatus==INCORRECT_FRAME)
{
//select yellow color for label,to show that it is sending incorrect frames
palette.setColor(QPalette::Window,QColor(Qt::yellow));
mLabel->setText("SYSTEM(I)");
}
//Set the color on the Label
mLabel->setPalette(palette);
}
A strange side effect of this situation is it compiles when I cast all the calls to ShowStatus() as
ShowStatus((StatusSubsystem)INCORRECT_FRAME);
Though this removes any compilation error, but a strange thing happens. Though I make call to INCORRECT_FRAME above but in function definition it matches with ENABLED. How on earth is that possible? Its like while passing INCORRECT_FRAME by reference, it magically converts to ENABLED, which should be impossible. This is driving me nuts.
Can you find any flaw in what I am doing? or is it something else?
The application is made using C++,Qt-4.2.1 on RHEL4.
Thanks.
You should take the enum by value, rather than by const reference. It's small enough to fit into an int, so there is no performance penalty or anything like it.
But, from what you're describing, it sounds like somebody has #defined INCORRECT_FRAME to 0 elsewhere. You should put something like the following in the line above it:
#ifdef INCORRECT_FRAME
#error Whoops, INCORRECT_FRAME already defined!
#endif
BTW, the #ifndef thingy (for your header files) is called an include guard. :-)
Related
This is my first question ever posted, so please let me know if there is anything that needs changes in my post :)
I am currently working on a dialog that is supposed to let the user change the background-color for some signal plotting. The "wxColourPickerCtrl" seems to do exactly what I need. Since there are multiple plots/pictures to be manipulated, the ColourPickerCtrls are initialized in a loop with the chosen background color as the default value:
for (const auto& [signalName, signalProperties] : properties)
{
wxColourPickerCtrl* selectBackgroundColor = new wxColourPickerCtrl(this, signalProperties.first, signalProperties.second.backgroundColor, wxDefaultPosition, wxDefaultSize);
}
"this" is an object of type SignalPropertiesDialog, which is directly inherited from wxDialog.
I have left out all the necessary sizer stuff, since it's not relevant for the problem (at least imo). "properties" is structured as follows:
std::map<std::string, std::pair<int, GraphPicture::Properties>> signalProperties_;
where GraphPicture::Properties contains the properties I want to manipulate:
struct Properties
{
wxColour backgroundColor{ *wxWHITE };
wxColour lineColor{ *wxBLACK };
int linewidth_px{ 1 };
bool isShown{ true };
};
The application successfully builds but immediately crashes on startup while generating those color picker objects.
wxIshiko has uploaded multiple tutorials and code snippets as examples for various wxWidgets controls, including the wxColourPickerCtrl. So I downloaded the sample code and tried to run it. Surprisingly, it worked.
While running through the code step by step I noticed the following difference:
The wxColourPickerCtrl is based on wxPickerBase. The wxPickerBase is created by calling the constructor of wxColourPickerCtrl (what I am actually doing in my code). During the construction of the wxPickerBase, the desired color is called by the name wxColourDataBase::FindName(const wxColour& color) const where the wxColourBase itself is instantiated. This is where the difference is:
When running the code snippet by wxIshiko, wxColourDataBase is instantiated correctly including the member m_map of type wxStringToColourHashMap* which is set to be NULL.
When running the code written by myself, wxColourDataBase is not correctly instantiated, and thus the member m_map is not set to be NULL, which leads to to the crash.
I have the feeling that there is nothing wrong with the way I set up the wxColourPickerCtrls. I somehow think there is a difference in the solution properties of the projects. I checked those but was not able to find any relevant differences.
I would really appreciate any hint or help since I am completely stuck on that problem.
Thank you very much in advance and have a good one,
Alex
EDIT:
I attached a screeny of the call stack.
Call stack
When does this code run exactly? If it is done after the library initialization (which would be the case, for example, for any code executed in your overridden wxApp::OnInit()), then wxTheColourDatabase really should be already initialized and what you observe should be impossible, i.e. if it happens it means that something is seriously wrong with your library build (e.g. it doesn't match the compiler options used when compiling your applications).
As always with such "impossible" bugs, starting with a known working code and doing bisection by copying parts of your code into the working version until it stops working will usually end up by finding a bug in your code.
I added a file in source control which had an enum definition as:
enum { OK = 0, ERROR };
But on compilation it was throwing errors like "expected identifier before numeric constant."
Did my research on that and the culprit was supposed to be 'OK' which was defined somewhere else in the code. So, i changed OK with say, OK_1, and the issue was, indeed, resolved.
However, I have not been able to find where in my code base was this 'OK' defined before.
I ran a grep from top level and couldn't find it. I am pretty sure I have covered all the application related code, but OK wasn't there.
I think it's unlikely that it was a part of some shared library as compilation process didn't even reach linking phase. It could have come from one of the header files maybe.
Is there a way/linux tool that somehow can be tricked to find where this OK is coming from?
If you are using C++ 11 take a look at enum class:
http://www.cprogramming.com/c++11/c++11-nullptr-strongly-typed-enum-class.html
One big draw back of enum is that you cant have 2 enums with the same name.
With enum class this draw back is gone, you can write thing like this:
enum class Color {RED, GREEN, BLUE};
enum class Feelings {EXCITED, MOODY, BLUE};
And later on in the code:
Color color = Color::GREEN;
if ( Color::RED == color )
{
// the color is red
}
Code example is pasted from linked www page
Converting my comment to answer.
Looks like you need pre-processor output Can gcc output C code after preprocessing?
my English is not good,but you can try enum var{xxx,xxx},you can customize var.
I think this would increase the quality of life when devving, but google came up with nothing and I couldn't find anything specific inside inside Netbeans either.
What I want is to start with this header:
class bla
{
public:
static void gfg(somearg asd);
};
Then I open the blank bla.cpp and pressed 'autoimplement'. After that, it would look like this:
#include "bla.h"
static void bla::gfg(somearg asd)
{
//TODO: implement
throw unimplemented("void bla::gfg(somearg) is unimplemented");
}
Anyone know of a tool like this?
I found http://www.radwin.org/michael/projects/stubgen/
"stubgen is a C++ development tool that keeps code files in sync with their associated headers. When it finds a member function declaration in a header file that doesn't have a corresponding implementation, it creates an empty skeleton with descriptive comment headers."
This looks like it does exactly what you want it to do.
Some time has passed and in the meantime the requested feature seems to have been implemented in netbeans. Refer to https://netbeans.org/bugzilla/show_bug.cgi?id=213811 , which also gives a description on how to use it:
Note:
Implemented CTRL+SPACE.
IDE suggest implementing of class method if CTRL+SPACE was pressed:
- inside file that already has at least one method definition
- between method declarations
Yes I am a begginer. I am reading a book on cocos2d development. The author wrote this book using 0.99.4. In the book, it says to call a function that creates sprites and adds them to an array by using the following code: [self initSpiders];. But when I run this, I get a warning that says "'Gamescene may not respond to'-resetSpiders'". I am assuming that there is an updated way of doing this in the newer version of cocos2d. If there is, I would be thankful if someone could explain the proper way of going about this. If this is the correct way, then what am I doing wrong? Thanks in advance.
In objective-c, an object tells a message to do something:
[someObject doSomething];
Or with an argument:
[someObject doSomethingWithArgument:someValue];
The message you get from the compiler is telling you that the object (eg. "someObject") does not understand what you are telling it to do (doSomething).
To make that compiler warning go away, check the following:
Did you #include the header file of the class your "someObject" is an instance of?
Does that header file in fact have the method you are calling? (including arguments?)
If you are calling a method you wrote, make sure you put that method in the header file. If you are calling a method that someone else wrote, or is part of the OS; make sure you include the header file, then perhaps find the method in the header file and copy/paste it into your code. This will make sure you get the EXACT method signature. These two are not the same:
[self generateSprites]; // note the capitol S
[self generatesprites]; // method names are case sensitive
If you need a better answer, you'll need to post some of your code so that people can see what you're doing wrong.
Hi I have just started using C++ today, and I am working on checkboxes. I have tried using CheckBox1->Checked in an if statement or whatever, but it isn't working.
The error is:
Error 2 error C2227: left of '->Checked' must point to class/struct/union/generic type
EDIT: The Code is:
void function ()
{
if (1001->Checked)
{
Sleep(2000);
}
}
Without seeing some of your code, it's very difficult to offer targeted assistance.
However, that error message usually comes about because the item you're de-referencing is not a pointer.
Check to ensure it's of the correct type. It should be something along the lines of:
tCheckBox *CheckBox1;
One possibility is that you've declared it not as a pointer to the checkbox but as a checkbox itself:
tCheckBox CheckBox1;
Note the lack of the asterisk there that would otherwise mark it as a pointer. In that case, you would use CheckBox1.Checked rather than CheckBox1->Checked, if it's allowed by the framework (this isn't standard C++ since that beast has no concept of GUI libraries).
If that doesn't help, please post the code so we can offer better suggestions.
Update:
if (1001->Checked) ?????
1001 is not a pointer - it's not a variable of any description, it's an integer constant.
You need to declare and use a variable of some description. First step is, I think, to read up on the documentation for your framework and/or get some sample code that does compile and work, basing your initial work of that.
Use CButton::GetCheck() to determine the state of the checkbox - like so...
CButton* pButton = (CButton*) GetDlgItem(IDC_CHECKBOX_RESOURCE_ID);
if ( BST_CHECKED == pButton->GetCheck() )
{
// button is checked
}