Type [`info variables`](http://sourceware.org/gdb/current/onlinedocs/gdb/Symbols.html#index-info-variables-918) to list &quot;All global and static variable names&quot; (huge list.

Type [`info locals`](http://sourceware.org/gdb/current/onlinedocs/gdb/Frame-Info.html#index-info-locals-435) to list &quot;Local variables of current stack frame&quot; (names and values), including static variables in that function.

Type [`info args`](https://sourceware.org/gdb/current/onlinedocs/gdb/Frame-Info.html#index-info-args) to list &quot;Arguments of the current stack frame&quot; (names and values).

In case you want to see the local variables of a calling function use `select-frame` before `info locals`

E.g.:

    (gdb) bt
    #0  0xfec3c0b5 in _lwp_kill () from /lib/libc.so.1
    #1  0xfec36f39 in thr_kill () from /lib/libc.so.1
    #2  0xfebe3603 in raise () from /lib/libc.so.1
    #3  0xfebc2961 in abort () from /lib/libc.so.1
    #4  0xfebc2bef in _assert_c99 () from /lib/libc.so.1
    #5  0x08053260 in main (argc=1, argv=0x8047958) at ber.c:480
    (gdb) info locals
    No symbol table info available.
    (gdb) select-frame 5
    (gdb) info locals
    i = 28
    (gdb) 

In addition, since `info locals` does not display the arguments to the function you&#39;re in, use

    (gdb) info args

For example:

    int main(int argc, char *argv[]) {
        argc = 6*7;    //Break here.
        return 0;
    }

`argc` and `argv` won&#39;t be shown by `info locals`. The message will be &quot;No locals.&quot;

Reference: [info locals command][1].


  [1]: http://visualgdb.com/gdbreference/commands/info_locals

I want to keep a backup of all my MySQL databases. I have more than 100 MySQL databases. I want to export all of them at the same time and again import all of them into my MySQL server at one time. How can I do that?

Export and Import all MySQL databases at one time

I want to customize a scrollbar with CSS.

I use this WebKit CSS code, which works well for Safari and Chrome:

```lang-css
::-webkit-scrollbar {
  width: 15px;
  height: 15px;
}

::-webkit-scrollbar-track-piece {
  background-color: #c2d2e4;
}

::-webkit-scrollbar-thumb:vertical {
  height: 30px;
  background-color: #0a4c95;
}
```

How can I do the same thing in Firefox?

I know I can easily do it using jQuery, but I would prefer to do it with pure CSS if it&#39;s doable.

Custom CSS Scrollbar for Firefox

How can I print all global variables/local variables? Is that possible in gdb?

Printing all global variables/local variables?

<p>How can I print all global variables/local variables? Is that possible in gdb?</p>


In C (not C++/C#) how do I check if a variable is of a certain type?

For example, something like this:

    double doubleVar;
    if( typeof(doubleVar) == double ) {
        printf(&quot;doubleVar is of type double!&quot;);
    }

Or more general: How do I compare two types so that `compare(double1,double2)` will evaluate to true, and `compare(int,double)` will evaluate to false. Also I&#39;d like to compare structs of different composition as well.

Basically, I have a function that operates on variables of type &quot;struct a&quot; and &quot;struct b&quot;. I want to do one thing with the &quot;struct a&quot; variables and the other with the &quot;struct b&quot; variables. Since C doesn&#39;t support overloading and the `void` pointer losses its type information I need to check for type. BTW, what would be the sense in having a `typeof` operator, if you can&#39;t compare types?

&lt;hr/&gt;

The sizeof method seems to be a practical workaround solution for me. Thanks for your help. I still find it a bit strange since the types are known at compile time, but if I imagine the processes in the machine I can see, why the information is not stored in terms of types, but rather in terms of byte size. Size is the only thing really relevant besides addresses.


How do I check if a variable is of a certain type (compare two types) in C?

I am not an expert, so go easy on me.  Are there any differences between these two code segments?

    #define BIT3 (0x1
    &lt;
    &lt;
    3)
    static int a;

and

    #define BIT3 (0x1 &lt;&lt; 3) static int a;

Also, is there a way to write the first in one line?  What is the point of this multi-line style?  Is the following code good?

    #define BIT3 (0x1 &lt;&lt; 3)
    static int a;

Multi-line DEFINE directives?

I&#39;m using Ubuntu and I&#39;m also using Geany and CodeBlock as my IDE.
What I&#39;m trying to do is reading a string (like `&quot;Barack Obama&quot;`) and put it in a variable:

&lt;!-- language: c --&gt;

    #include &lt;stdio.h&gt;
    
    int main(void)
    {
    	char name[100];

    	printf(&quot;Enter your name: &quot;);
    	scanf(&quot;%s&quot;, name);
    	printf(&quot;Your Name is: %s&quot;, name);

    	return 0;
    }

Output:

&lt;!-- language: none --&gt;

    Enter your name: Barack Obama
    Your Name is: Barack

How can I make the program read the whole name?

Reading string from input with space character?

I am porting an application from Tru64 to Linux and it uses PID_MAX defined in limits.h.
Linux doesn&#39;t have that define. 
How do I find PID_MAX in **c** without reading `/proc/sys/kernel/pid_max` by hand?
Is there a library?

Maximum PID in Linux

When I try to build this code

    inline void f() {}
    
    int main()
    {
        f();
    }

using the command line

    gcc -std=c99 -o a a.c

I get a linker error (undefined reference to `f`).  The error vanishes if I use `static inline` or `extern inline` instead of just `inline`, or if I compile with `-O` (so the function is actually inlined).

This behaviour seems to be defined in paragraph 6.7.4 (6) of the C99 standard:
&gt; If all of the file scope declarations for a function in a translation unit include the `inline` function specifier without `extern`, then the definition in that translation unit is an inline definition. An inline definition does not provide an external definition for the function, and does not forbid an external definition in another translation unit. An inline definition provides an alternative to an external definition, which a translator may use to implement any call to the function in the same translation unit. It is unspecified whether a call to the function uses the inline definition or the external definition.

If I understand all this correctly, a compilation unit with a function defined `inline` as in the above example only compiles consistently if there is also an external function with the same name, and I never know if my own function or the external function is called.

Isn&#39;t this behaviour completely daft? Is it ever useful to define a function `inline` without `static` or `extern` in C99?  Am I missing something?

## Summary of answers

Of course I was missing something, and the behaviour isn&#39;t daft. :)

As [Nemo explains](https://stackoverflow.com/questions/6312597/is-inline-without-static-or-extern-ever-useful-in-c99/6312813#6312813), the idea is to put the *definition* of the function

    inline void f() {}

in the header file and only a *declaration*

    extern inline void f();

in the corresponding .c file.  Only the `extern` declaration triggers the generation of externally visible binary code.  And there is indeed no use of `inline` in a .c file -- it&#39;s only useful in headers.

As the [rationale of the C99 committee quoted in Jonathan&#39;s answer](https://stackoverflow.com/questions/6312597/is-inline-without-static-or-extern-ever-useful-in-c99/6312854#6312854) explicates, `inline` is all about compiler optimisations that require the definition of a function to be visible at the site of a call.  This can only be achieved by putting the definition in the header, and of course a definition in a header must not emit code every time it is seen by the compiler.  But since the compiler is not forced to actually inline a function, an external definition must exist somewhere.

Is &quot;inline&quot; without &quot;static&quot; or &quot;extern&quot; ever useful in C99?

I&#39;m currently using the iOS 5 SDK trying to develop my app.
I&#39;m trying to make an NSString a property, and then to synthesize it in the .m file (I have done this before with no issues). Now, I came across this: &quot;Semantic Issue: Property&#39;s synthesized getter follows Cocoa naming convention for returning &#39;owned&#39; objects.&quot;

This is my code:
.h

    @interface ViewController : UIViewController {
         NSString *newTitle;
    }
    @property (strong, nonatomic) NSString *newTitle;
.m

    @synthesize newTitle;

Does anyone have a clue how I could fix this? 
Thanks!!

Semantic Issue: Property&#39;s synthesized getter follows Cocoa naming convention for returning &#39;owned&#39; objects

I&#39;m echoing some text in a bash script with a variable in it, and want to pad that variable so it will always have the appropriate ammount of spaces to the right to keep the rest of the text aligned.

Here&#39;s an example of what I want:

    Echoing random number 1080    [ OK ]
    Echoing random number 443     [ OK ]
    Echoing random number 34842   [ OK ]

The numerical value would be of varying length (probably no longer than 5 or 6 digits).

I know that printf can do this and right align the variable by doing the following:

    printf &quot;Echoing random number %5s   [ OK ]&quot; $RAND_NUM

However, this would format the text like this:

    Echoing random number  1080   [ OK ]
    Echoing random number   443   [ OK ]
    Echoing random number 34842   [ OK ]

And of course just echoing with spaces doens&#39;t work:

    echo &quot;Echoing random number ${RAND_NUM}   [ OK ]&quot;

Produces this:

    Echoing random number 1080   [ OK ]
    Echoing random number 443   [ OK ]
    Echoing random number 34842   [ OK ]

Is there a way to print the text like my first example?

How do I print some text in bash and pad it with spaces to a certain width?

I am currently building a sales module for a clients website. So far I have got the sale price to calculate perfectly but where I have come stuck is formatting the output to 2 decimal places.

I am currently calling this in a variable so that I can data bind the results to a listview.

    Sale = float.Parse(((x.Sale_Price - (x.Sale_Price * (x.Discount_Price / 100))).ToString())),

Can anyone show me how to format the output to 2 decimal places?? Many Thanks!

Formatting a float to 2 decimal places

Does a Python equivalent to the Ruby `||=` operator (&quot;set the variable if the variable is not set&quot;) exist?

Example in Ruby :


     variable_not_set ||= &#39;bla bla&#39;
     variable_not_set == &#39;bla bla&#39;

     variable_set = &#39;pi pi&#39;
     variable_set ||= &#39;bla bla&#39;
     variable_set == &#39;pi pi&#39;

Python conditional assignment operator

Is there such a thing?

for eg

    $var = -5;
    echo thefunction($var); // should be 0
    
    
    $var = 5;
    echo thefunction($var); // should be 5

Default php function that turns negative numbers in 0

I am looking for a way to do some action when a particular break point hits in gdb. 

Basically I have some memleak in my program. When malloc and free function hits, I need to enter into the function (step) and collect some basic information like the addr and size (basically print there values). Once done resume my program.

Do we have any good way to do this?

How to do an specific action when a certain breakpoint is hit in GDB?

My program has a segmentation fault problem, but it faults rarely(once in 20 times or more), and to debug it in GDB, I need to manually rerun the program until the segmentation fault occurs (during a half day of reruns only once it fails :( ).

So the questions is, is there any way to tell the GDB to rerun program until some segfault?

How can I rerun a program with gdb until a segmentation fault occurs?

According to the documentation I can break on specific exception type by using conditional breakpoints. However the syntax for the condition isn&#39;t very clear to me:

    condition bnum &lt;expression&gt;

Looking at the expression syntax I think this is the pattern I need:

&gt; `{type} addr`

However, I don&#39;t know what I should pass for the `addr` argument. I tried the following:

    (gdb) catch throw
    (gdb) condition 1 boost::bad_function_call *

But it doesn&#39;t work (gdb breaks on all exception types).

Can anyone help?

&lt;hr/&gt;&lt;h3&gt;Update&lt;/h3&gt;
I also tried @Adam&#39;s suggestion, but it results in an error message:

    (gdb) catch throw boost::bad_function_call
    Junk at end of arguments.

Without `boost::` namespace:

    (gdb) catch throw bad_function_call
    Junk at end of arguments.

&lt;hr/&gt;&lt;h3&gt;Workaround&lt;/h3&gt;
Breaking in the constructor of `bad_function_call` works.

How to break when a specific exception type is thrown in GDB?

Every time, my application crash a core dump file is not generated. I remember that few days ago, on another server it **was** generated. I&#39;m running the app using screen in bash like this:

    #!/bin/bash
    ulimit -c unlimited
    while true; do ./server; done

As you can see I&#39;m using `ulimit -c unlimited` which is important if I want to generate a core dump, but it still doesn&#39;t generate it, when I got an segmentation fault.
How can I make it work?

Core dump file is not generated

I am new to GDB, so I have some questions:

* How can I look at content of the stack?
Example: to see content of register, I type `info registers`. For the stack, what should it be?

* How can I see the content of `$0x4(%esp)`? When I type `print /d $0x4(%esp)`, GDB gives an error.

Platform: Linux and GDB



How can one see content of stack with GDB?

I am working on a series of unit tests in Python, some of which depend on the value of a configuration variable. These variables are stored in a global Python config file and are used in other modules. I would like to write unit tests for different values of the configuration variables but have not yet found a way to do this.

I do not have the possibility to rewrite the signatures of the methods I&#39;m testing.

This is what I would like to achieve:

    from my_module import my_function_with_global_var

    class TestSomething(self.unittest):
    
        def test_first_case(self):
             from config import MY_CONFIG_VARIABLE
             MY_CONFIG_VARIABLE = True
             self.assertEqual(my_function_with_global_var(), &quot;First result&quot;)

        def test_second_case(self):
             from config import MY_CONFIG_VARIABLE
             MY_CONFIG_VARIABLE = False
             self.assertEqual(my_function_with_global_var(), &quot;Second result&quot;)

Thanks.

Edit: Made the example code more explicite.

Modifying global variables in Python unittest framework

At w3schools there is written:

&gt; If you declare a variable, without using &quot;var&quot;, the variable always becomes GLOBAL.

Is it useful to declare global variable inside the function? I can imagine to declare some global variables in some event handler, but what is it good for? Better usage of RAM?

Declaring variables without var keyword

We have a lot of setup JS code that defines panels, buttons, etc that will be used in many other JS files.

Typically, we do something like:

**grid.js**

    var myGrid = .....


**combos.js**

    var myCombo = .....

Then, in our application code, we:

**application.js**

    function blah() {
        myGrid.someMethod()
    }

**someother.js**

    function foo() {
        myCombo.someMethod();
        myGrid.someMethod();
    }

So, should we be using the `var myGrid` or is better to use `window.myGrid`

What&#39;s the difference?


Should I use window.variable or var?

I was wondering how to implement a global logger that could be used everywhere with your own settings:

I currently have a custom logger class:

    class customLogger(logging.Logger):
       ...

The class is in a separate file with some formatters and other stuff.
The logger works perfectly on its own.

I import this module in my main python file and create an object like this:

    self.log = logModule.customLogger(arguments)

But obviously, I cannot access this object from other parts of my code.
Am i using a wrong approach? Is there a better way to do this?

Python: logging module - globally

&gt; **Possible Duplicate:**  
&gt; [Static vs global](https://stackoverflow.com/questions/2271902/static-vs-global)  

&lt;!-- End of automatically inserted text --&gt;

I&#39;m confused about the differences between global and static global variables. If static means that this variable is global only for the same file then why in two different files same name cause a name collisions?

Can someone explain this?

Content Type	Original Author	Original Content on Stackoverflow
Question	cpuer	View Question on Stackoverflow
Solution 1 - C	kennytm	View Answer on Stackoverflow
Solution 2 - C	Samuel Åslund	View Answer on Stackoverflow
Solution 3 - C	Evgeni Sergeev	View Answer on Stackoverflow

Printing all global variables/local variables?

C Problem Overview

C Solutions

Solution 1 - C

Solution 2 - C

Solution 3 - C

Custom CSS Scrollbar for Firefox

Export and Import all MySQL databases at one time

Attributions