QString Error

[marvic_39]

Hello,

What is wrong in this statement, it worked on another machine.

On my machine ( VMWare) flashing error.

QString settingsFile{"/neet/one.json"};

Error Message

/home/cpp/cap.h:108: error: function definition does not declare parameters

Answers Appreciated.

[kshegunov]

Hello,
This is not a Qt problem, your C++ syntax is wrong. Function arguments (constructors included) are surrounded by parenthesis, not with curly braces.

Kind regards.

[marvic_39]

Thank you for replay, i changed to circle brackets

QString settingsFile("/neet/one.json");

still It flashing error again.

/home/cpp/cap.h:108: error: expected identifier before string constant
/home/cpp/cap.h:108: error: expected ',' or '...' before string constant```

Thank You.

[mrjj]

@marvic_39 said:
and you do have
#include <QString>
?

[marvic_39]

@mrjj

Yes, #include <QString>
As well
#include <QtCore>

[mrjj]

@marvic_39
can it be error from lines above it as

#include <QString>
QString settingsFile("/boot/settings.json");

surely compiles.

check if lines above has ; in the end

[marvic_39]

@mrjj

This is the statement, Still errors

QString settingsFile("/neet/one.json");

And header
#include <QString>

[kshegunov]

Ok, the statement is valid. Where is this located, in your header? It's not a good idea to declare variables in headers. Also, how do you compile (what environment/compiler) are you using?

[marvic_39]

@kshegunov

Where you declare variables?

[kshegunov]

@marvic_39
Usually where you use them, in functions or blocks. If you have a global variable then it is declared in the .cpp file, thus you don't get the same symbol in multiple translation units (.o files resulting from compilation). It is safe to put extern declarations in header files, because they do not amount to a variable, but are only information for the compiler (and linker).
This most certainly is a C++ problem. My suggestion is to read up a bit more on C++ to have a better grasp on where and for what memory is allocated. That being said, without a bit more of code and/or information on the problem you're facing I fear I wouldn't be of much help.

Here are some resources you could use, if you wish:
http://www.learncpp.com/cpp-tutorial/13-a-first-look-at-variables-initialization-and-assignment/
http://www.learncpp.com/cpp-tutorial/41-blocks-compound-statements/
http://www.learncpp.com/cpp-tutorial/42-global-variables/
https://en.wikipedia.org/wiki/Call_stack

[marvic_39]

@kshegunov

I am aware of C++, It looks good, If you provide a solution, how to solve this single statement. You do not need to be proficient.

[Ratzz]

@marvic_39
Might be problem with GCC.Check your Gcc version .

[marvic_39]

@Ratzz

Other apps and examples are working fine and executing properly.

[hskoglund]

Hi, just guessing, but if that line is inside a class declaration (not outside) then you'll get that 108 error, for example:

class MyClass {
...
QString settingsFile("/boot/settings.json");
...
};

you could try

class MyClass {
...
QString settingsFile = "/boot/settings.json";
...
};

[marvic_39]

@hskoglund

Yes, tried that statement too. Here it's flashing error.

QString settingsFile = "/neet/one.json";

/home/cpp/cap.h:109: sorry, unimplemented: non-static data member initializers

/home/cpp/cap.h:109: error: in-class initialization of static data member 'str' of non-literal type

[Ratzz]

@hskoglund
What is your GCC version ? less than 4.7?

[marvic_39]

@Ratzz

gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3

I cross compiled Linux, OpenCV, FFmpeg Qt Raspi and many other apps never faced a compiler problems.

Should this look like compiler version problem?

[Ratzz]

@marvic_39 said:
But Non static data member initializers available only for GCC >4.7 . Check this . Check the GCC support docs.

[marvic_39]

@Ratzz

Thank you, Ok, Will check with updated GCC version greater than 4.7.

[marvic_39]

@Ratzz

Installed, Still flashing errors.

gcc (Ubuntu/Linaro 4.7.3-2ubuntu1~12.04) 4.7.3

108   QString settingsFile("Hello");
109   QString str="/neet/one.json";

/home/cpp/app.h:108: error: expected identifier before string constant
/home/cpp/app.h:108: error: expected ',' or '...' before string constant

/home//cpp/app.h:109: sorry, unimplemented: non-static data member initializers
/home/cpp/app.h:109: error: in-class initialization of static data member 'str' of non-literal type

In QT creator it show this, is this correct.

Qt Creator 3.5.1 (opensource)
Based on Qt 5.5.1 (GCC 4.9.1 20140922 (Red Hat 4.9.1-10), 32 bit)

Built on Oct 13 2015 07:38:32

[Ratzz]

@marvic_39
Are you doing this inside the structure? QString settingsFile("Hello");
Is the error at line 108 bec of this ?

[marvic_39]

@Ratzz

I cleaned all GCC versions and activated 4.7
Now it's compiled and executed my app.

QString settingsFile{"neet/One.json"};

Very strange about the brackets () and {}

Thank You guys, it's GCC 4.7 made the difference.

[Ratzz]

@marvic_39
Once your problem is solved please use the Topic Tools button to mark as Solved.
Thank you!

[kshegunov]

Ok. I think I get what your problem was. In all probability C++11 is enabled by default in GCC 4.7 (on your distribution), that is why I asked what compiler and environment you're using. Here is the relevant link:
http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2008/n2756.htm
That being said, without the non-static data member initializers supported by the compiler you are obliged to initialize the object in your class' constructor and cannot do it in its declaration. Meaning that if you compile the code on another platform and/or compiler that does not have the C++11 standard enabled you'll get similar errors.