The differences are combinations  of:

 1. **L vs V**: whether    you want to pass the     parameters to       the exec&#39;ed    program as
    
    * **L**: individual parameters in the call (variable argument list): `execl()`, `execle()`, `execlp()`, and `execlpe()`
    * **V**: as    an array of char* `execv()`, `execve()`, `execvp()`, and `execvpe()`
    
    The array       format is    useful when the number of     parameters that are to be sent to    the    exec&#39;ed process are variable    -- as in    not known in advance, so you can&#39;t       put in a fixed    number of parameters      in a    function call.
      
 2. **E**: The versions with an &#39;e&#39; at the end let you additionally pass an    array of char* that are a set of        strings added to the spawned     processes environment before the     exec&#39;ed program launches.  Yet    another way of passing parameters,    really.
      
 4. **P**: The versions with &#39;p&#39; in there use the environment variable `PATH`
    to    search for the executable file    named     to execute. The versions    without the     &#39;p&#39; require an    absolute or relative      file path    to be prepended to the     filename of the executable if it is     not in the current working    directory.

Opengroup are one of the best general references for core c/c++ functions.

The docs for exec* are here: http://pubs.opengroup.org/onlinepubs/009695399/functions/environ.html

It&#39;s Posix extension of C runtime library. If official Posix documentation is insufficiently then I can recomend book - Samuel P. Harbison, Guy L.Steele, 2002 &quot;C A Reference&quot; Page# 416 - cover that question.




I am waiting for another developer to finish a piece of code that will return an np array of shape (100,2000) with values of either -1,0, or 1.

In the meantime, I want to randomly create an array of the same characteristics so I can get a head start on my development and testing. The thing is that I want this randomly created array to be the same each time, so that I&#39;m not testing against an array that keeps changing its value each time I re-run my process.

I can create my array like this, but is there a way to create it so that it&#39;s the same each time. I can pickle the object and unpickle it, but wondering if there&#39;s another way.

    r = np.random.randint(3, size=(100, 2000)) - 1


Consistently create same random numpy array

If have the following plural ressource in my strings.xml:

       &lt;plurals name=&quot;item_shop&quot;&gt;
            &lt;item quantity=&quot;zero&quot;&gt;No item&lt;/item&gt;
            &lt;item quantity=&quot;one&quot;&gt;One item&lt;/item&gt;
            &lt;item quantity=&quot;other&quot;&gt;%d items&lt;/item&gt;
       &lt;/plurals&gt;	

I&#39;m showing the result to the user using:

    textView.setText(getQuantityString(R.plurals.item_shop, quantity, quantity));

It&#39;s working well with 1 and above, but if quantity is 0 then I see &quot;0 items&quot;. 
Is &quot;zero&quot; value supported only in Arabic language as the documentation seems to indicate?
Or am I missing something?

Android plurals treatment of &quot;zero&quot;

These are all the versions of exec that can be used in C (and C++)

    execl
    execle
    execlp
    execv
    execve
    execvp

What&#39;s the difference between them? How do you know which one to use?

What are the different versions of exec used for in C and C++?

<p>These are all the versions of exec that can be used in C (and C++)</p>
<pre><code class="hljs">execl
execle
execlp
execv
execve
execvp
</code></pre>
<p>What's the difference between them? How do you know which one to use?</p>


Is there a reason when a function **should return a RValue Reference**? A technique, or trick, or an idiom or pattern?

    MyClass&amp;&amp; func( ... );

I am aware of the danger of [returning references][1] in general, but sometimes we do it anyway, don&#39;t we? `T&amp; T::operator=(T)` is just one idiomatic example. But how about `T&amp;&amp; func(...)`? Is there any general place where we would gain from doing that? Probably different when one writes library or API code, compared to just client code?

  [1]: https://stackoverflow.com/questions/3033689/question-about-r-value-in-c0x

Is there any case where a return of a RValue Reference (&amp;&amp;) is useful?

There is *Copy to Output Directory* property for files in C# projects. But in VC++ projects it is absent. I know, that I can use *Build events* in VC++ and write there something like

    xcopy /y /d %(FullPath) $(OutDir)

Is there a way to avoid the use of CMD (and other scripting methods)? Can msbuild do something to help in this case?

Automatic copy files to output during application building

Why does this line give the error `Error: incomplete type is not allowed`?

    stringstream ss;

Incomplete type is not allowed: stringstream

I&#39;ve got a (generated) literal string in C++ that may contain characters that need to be escaped using the `\x` notation. For example:

    char foo[] = &quot;\xABEcho&quot;;

However, g++ (version 4.1.2 if it matters) throws an error:

    test.cpp:1: error: hex escape sequence out of range

The compiler appears to be considering the `Ec` characters as part of the preceding hex number (because they look like hex digits). Since a four digit hex number won&#39;t fit in a `char`, an error is raised. Obviously for a wide string literal `L&quot;\xABEcho&quot;` the first character would be U+ABEC, followed by `L&quot;ho&quot;`.

It seems this has changed sometime in the past couple of decades and I never noticed. I&#39;m almost certain that old C compilers would only consider *two* hex digits after `\x`, and not look any further.

I can think of one workaround for this:

    char foo[] = &quot;\xAB&quot;&quot;Echo&quot;;

but that&#39;s a bit ugly. So I have three questions:

- When did this change?

- Why doesn&#39;t the compiler only accept &gt;2-digit hex escapes for wide string literals?

- Is there a workaround that&#39;s less awkward than the above?

When did C++ compilers start considering more than two hex digits in string literal character escapes?

I found these symbols in a function declaration several times, but I don&#39;t know what they mean.

**Example:**

    void raccogli_dati(double **&amp; V, double **p, int N) { 
      int ultimo = 3; 
      V = new double * [N/2]; 
      for(int i=0; i &lt; N/2; i++) { 
        V[i] = new double[N/2], std :: clog &lt;&lt; &quot;digita &quot; &lt;&lt; N/2 - i
                     &lt;&lt; &quot; valori per la parte superiore della matrice V: &quot;; 
        for(int j=i; j &lt; N/2; j++) 
          std :: cin &gt;&gt; V[i][j], p[ultimo++][0] = (V[i][j] /= sqrt(p[i][0]*p[j][0]));
      } 
      for(int i=1; i &lt; N/2; i++) 
        for(int j=0; j &lt; i; j++) 
           V[i][j] = V[j][i];
    }


Meaning of *&amp; and **&amp; in C++

How can I check if a `float` variable contains an integer value? So far, I&#39;ve been using:

    float f = 4.5886;
    if (f-(int)f == 0)
         printf(&quot;yes\n&quot;);
    else printf(&quot;no\n&quot;);

But I wonder if there is a better solution, or if this one has any (or many) drawbacks.


Checking if float is an integer

I have two postcodes `char*` that I want to compare, ignoring case.
Is there a function to do this?

Or do I have to loop through each use the `tolower` function and then do the comparison?

Any idea how this function will react with numbers in the string

Thanks

Case Insensitive String Comparison in C

AFAIK, C supports just a few data types:

    int, float, double, char, void enum.

I need to store a number that could reach into the high 10 digits.  Since I&#39;m getting a low 10 digit # from 

&gt; INT_MAX

, I suppose I need a double.

`&lt;limits.h&gt;` doesn&#39;t have a `DOUBLE_MAX`.  I found a `DBL_MAX` on the internet that said this is LEGACY and also appears to be C++.  Is double what I need?  Why is there no `DOUBLE_MAX`?

How do I get DOUBLE_MAX?

How can I tell where g++ was able to find an include file?  Basically if I

    #include &lt;foo.h&gt;

g++ will scan the search path, using any include options to add or alter the path.  But, at the end of days, is there a way I can tell the absolute path of foo.h that g++ chose to compile?  Especially relevant if there is more than one foo.h in the myriad of search paths.

Short of a way of accomplishing that... is there a way to get g++ to tell me what its final search path is after including defaults and all include options?

How to tell where a header file is included from?

How to add multiple header include and library directories to the search path in a single gcc command?

Is it possible to execute an external program from within node.js? Is there an equivalent to Python&#39;s `os.system()` or any library that adds this functionality?

How to execute an external program from within Node.js?

Consider the following code:

    String commandf = &quot;ls /etc | grep release&quot;;
  
    try {

        // Execute the command and wait for it to complete
        Process child = Runtime.getRuntime().exec(commandf);
        child.waitFor();

        // Print the first 16 bytes of its output
        InputStream i = child.getInputStream();
        byte[] b = new byte[16];
        i.read(b, 0, b.length); 
        System.out.println(new String(b));
	
    } catch (IOException e) {
        e.printStackTrace();
        System.exit(-1);
    }

The program&#39;s output is:

    /etc:
    adduser.co

When I run from the shell, of course, it works as expected:

    poundifdef@parker:~/rabbit_test$ ls /etc | grep release
    lsb-release

The internets tell me that, due to the fact that pipe behavior isn&#39;t cross-platform, the brilliant minds who work in the Java factory producing Java can&#39;t guarantee that pipes work.

How can I do this?

I am not going to do all of my parsing using Java constructs rather than `grep` and `sed`, because if I want to change the language, I&#39;ll be forced to re-write my parsing code in that language, which is totally a no-go.

How can I make Java do piping and redirection when calling shell commands?

How to make pipes work with Runtime.exec()?

What is the difference between the following Ruby methods?

`exec`, `system` and `%x()` or *Backticks*

I know they are used to execute terminal commands programmatically via Ruby, but I&#39;d like to know why there are three different ways to do this.

Ruby, Difference between exec, system and %x() or Backticks

I&#39;m struggling to understand the difference between `shell_exec()` and `exec()`...

I&#39;ve always used `exec()` to execute server side commands, when would I use `shell_exec()`?

Is `shell_exec()` just a shorthand for `exec()`?  It seems to be the same thing with fewer parameters.

PHP shell_exec() vs exec()

I&#39;m trying to get simple output by exec task with `msbuild`:

    &lt;Project xmlns=&quot;http://schemas.microsoft.com/developer/msbuild/2003&quot;&gt;
      &lt;Target Name=&quot;Test&quot;&gt;
        &lt;Exec Command=&quot;echo test output&quot;&gt;
          &lt;Output TaskParameter=&quot;Outputs&quot; ItemName=&quot;Test1&quot; /&gt;
        &lt;/Exec&gt;
        &lt;Exec Command=&quot;echo test output&quot;&gt;
          &lt;Output TaskParameter=&quot;Outputs&quot; PropertyName=&quot;Test2&quot; /&gt;
        &lt;/Exec&gt;
        &lt;Message Text=&quot;----------------------------------------&quot;/&gt;
        &lt;Message Text=&quot;@(Test1)&quot;/&gt;
        &lt;Message Text=&quot;----------------------------------------&quot;/&gt;
        &lt;Message Text=&quot;$(Test2)&quot;/&gt;
        &lt;Message Text=&quot;----------------------------------------&quot;/&gt;
      &lt;/Target&gt;
    &lt;/Project&gt;

But get next output:

      echo test output
      test output
      echo test output
      test output
      ----------------------------------------
      ----------------------------------------
      ----------------------------------------

How can I get output by my script?

Content Type	Original Author	Original Content on Stackoverflow
Question	node ninja	View Question on Stackoverflow
Solution 1 - C++	Christo	View Answer on Stackoverflow
Solution 2 - C++	IanNorton	View Answer on Stackoverflow
Solution 3 - C++	Konstantin Burlachenko	View Answer on Stackoverflow

What are the different versions of exec used for in C and C++?

C++ Problem Overview

C++ Solutions

Solution 1 - C++

Solution 2 - C++

Solution 3 - C++

Android plurals treatment of "zero"

Consistently create same random numpy array

Attributions