[Differences between various standard modes][1]
----------------------------------------

&gt;clang supports the -std option, which changes what language mode clang uses. The supported modes for C are c89, gnu89, c94, c99, gnu99 and various aliases for those modes. If no -std option is specified, clang defaults to gnu99 mode.
&gt;
&gt;Differences between all c* and gnu* modes:
&gt;
&gt;* c* modes define `__STRICT_ANSI__`.
&gt;* Target-specific defines not prefixed by underscores, like &quot;linux&quot;, are defined in gnu* modes.
&gt;* Trigraphs default to being off in gnu* modes; they can be enabled by the `-trigraphs` option.
&gt;* The parser recognizes &quot;asm&quot; and &quot;typeof&quot; as keywords in gnu* modes; the variants `__asm__` and `__typeof__` are recognized in all modes.
&gt;* The Apple &quot;blocks&quot; extension is recognized by default in gnu* modes on some platforms; it can be enabled in any mode with the `-fblocks` option.

More links
----------

 * [Options controlling C dialect for GCC][3]
 * [Extensions to the C Language Family][2]
 * [Clang Language Extensions](http://clang.llvm.org/docs/LanguageExtensions.html)
 * https://stackoverflow.com/questions/3375697/useful-gcc-flags-for-c

  [1]: http://clang.llvm.org/docs/UsersManual.html
  [3]: http://gcc.gnu.org/onlinedocs/gcc/C-Dialect-Options.html#C-Dialect-Options
  [2]: http://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html

C99 is straight C99, GNU99 is C99 with gnu extensions. See the [GCC manpage][1].


  [1]: http://linux.die.net/man/1/gcc

C99 is simply the version of the C standard as of 1999 as we all know it. In GCC it is not fully supported.

GNU99 is an extension to C99, just like GNU98 is an extension of C98. From the docs:

&gt; ISO C99 plus GNU extensions. When ISO C99 is fully implemented in GCC, this will become the default. The name gnu9x is deprecated.

Clang supports these extensions also.


I am about to start implementing the data access infrastructure of a project that was architected with an approach to DDD (*it&#39;s my first attempt on DDD, so be gentle ;-)* ). 
 
I will be using Entity Framework. Until now, I was looking into the method teached by Julie Lerman on her great book, [Programming Entity Framework][1], where ***ADO.NET POCO Entity Generator*** is used, with some changes to the T4 templates and some more custom code.  
Today I started reading articles on EF4.1 and the ***ADO.NET DbContext Generator***, using ***Database First*** approach, and I&#39;m trying to decide with which one should I go.

DbContext and EF4.1&#39;s approach on DDD seems to be a nice, cleaner way than POCO Entities, but I&#39;m afraid that it could lead to some issues in the near future, since EF4.1 is still in RC.

From [ADO.NET team blog][2], I know that EF4.1 **does not** include:

 - Enum support
 - Spatial data type support
 - Stored Procedure support in Code First
 - Migration support in Code First
 - Customizable conventions in Code First

From my understanding, since I will be using ***Database First*** there is a smaller number of features that were not included.

In conclusion, my question is:  
**Can I replace *POCO Entities Generator* with EF4.1 DbContext Generator?**


  [1]: http://www.amazon.com/gp/product/0596807260?ie=UTF8&amp;tag=thdafa-20&amp;linkCode=as2&amp;camp=1789&amp;creative=390957&amp;creativeASIN=0596807260
  [2]: http://blogs.msdn.com/b/adonet/archive/2011/03/15/ef-4-1-release-candidate-available.aspx

ADO.NET DbContext Generator vs. ADO.NET Poco Entity Generator (ObjectContext)

How can I run an `EXE` program from a Windows Service using C#?

This is my code:

    System.Diagnostics.Process.Start(@&quot;E:\PROJECT XL\INI SQLLOADER\ConsoleApplication2\ConsoleApplication2\ConsoleApplication2\bin\Debug\ConsoleApplication2.exe&quot;);


When I run this service, the application is not starting.  
What&#39;s wrong with my code?

How can I run an EXE program from a Windows Service using C#?

I have saw the compiler option GNU99 and C99. What&#39;s the difference of them? Any detail documentation? (Clang, Xcode, Mac OS X)

What&#39;s the difference between GNU99 and C99 (Clang)?

<p>I have saw the compiler option GNU99 and C99. What's the difference of them? Any detail documentation? (Clang, Xcode, Mac OS X)</p>


What is the point of making a function static in C?

static function in C

So I&#39;ve come to like and enjoy using Google Test for a C++ project I&#39;m involved in.  I&#39;m just bringing up a new project that will be straight C (a library) and so far can&#39;t see any reason why not to continuing using Google Test, even though its a C++ framework.  Having a C++ compiler available will not be an issue.

Are there are specific reasons why I shouldn&#39;t use Google Test for testing straight C code?

Thanks.

Is Google Test OK for testing C code?

What would be your suggestion in order to create a single instance application, so that only one process is allowed to run at a time? File lock, mutex or what?

How to create a single instance application in C or C++

    int main ()
    {
       int a = 5,b = 2;
       printf(&quot;%d&quot;,a+++++b);
       return 0;
    }

This code gives the following error:

&gt; error: lvalue required as increment operand

But if I put spaces throughout `a++ +` and `++b`, then it works fine.
 

    int main ()
    {
       int a = 5,b = 2;
       printf(&quot;%d&quot;,a++ + ++b);
       return 0;
    }

What does the error mean in the first example?

Why doesn&#39;t a+++++b work?

My code is full of calls to &lt;code&gt;assert(condition)&lt;/code&gt;.
In the debug version I use &lt;code&gt;g++ -g&lt;/code&gt; which triggers my assertions.
Unexpectedly, the same assertions are also triggered in my release version, the one compiled without &lt;code&gt;-g&lt;/code&gt; option.

How can I completely disable my assertions at compile time? Should I explicitly define &lt;code&gt;NDEBUG&lt;/code&gt; in any build I produce regardless of whether they are debug, release or anything else?

How can I completely disable calls to assert()?

When I try to compile the piece of code below, I get this warning:

`warning: suggest parentheses around assignment used as truth value`

Why does this happen? This is a rather common idiom, I believe. I even use something like it earlier on my code.

    struct PIDList* 
    getRecordForPID(struct PIDList* list, pid_t pid) {
    	while(list = list-&gt;next)
    		if (list-&gt;pid == pid)
    			return list;
    
    	return NULL;
    }


Compiler warning - suggest parentheses around assignment used as truth value

I&#39;m running Eclipse Galileo. How do I enable assertions in Eclipse? 

As suggested by other sites, I&#39;ve tried adding the arguments: `-ea`.  I have also tried changing the compiler compliance level to `1.4`. Neither of those suggestions worked. 

Eclipse: enable assertions

This question has evolved over the past several weeks to cover more general issues with [tag:xcode4] (and upgrading projects form older [tag:xcode]s).

However many of the issues can be solved by following the same set of instructions.

If you have any of the following issues, try the methods in the accepted answer:

- Xcode 4 fails to archive an App
- Xcode 4 creates an unusable archive
- Xcode 4 does not create an .ipa
- Xcode 4 fails to compile due to preprocessor errors
- Xcode 4 cannot find headers
- Xcode 4&#39;s code complete is not working
- Project dependancies won&#39;t compile
- Adding a dependancy causes any of the above issues

## Original Question
Title: *&quot;lexical or preprocessor issue file not found&quot; in Xcode 4*

I have a project in Xcode 4 that will build fine and run on the device and simulator but when trying to Archive it errors when looking for headers files associated with a static library:

    In file included from /Volumes/Development/Path/LBProject/LBProject/LBProject-Prefix.pch:15:
    In file included from /Volumes/Development/Path/LBProject/LBFDefines.h:23:
    In file included from /Volumes/Development/Path/LBProject/Classes/LBProjectAppDelegate.h:11:
    In file included from /Volumes/Development/Path/LBProject/LBProject/../FKNDirectory/FKNDirectoryManager.h:10:
    /Volumes/Development/Path/LBProject/LBProject/../FKNDirectory/FKNDataModel.h:11:9: fatal error: &#39;Merchant.h&#39; file not found [1]
     #import &quot;Merchant.h&quot;
             ^
    1 error generated. 

Xcode gives the error

    lexical or preprocessor issue file not found 

*Much* Googling has show many people are having this issue but no solution. Anyone got a fix or even a clue. 

**Update:** The `user header` search paths are set to `${BUILT_PRODUCTS_DIR}` in all configurations. It builds fine using any configuration except when archiving. 

**Update 2:** `Merchant.h` is a Core Data class that is auto-generated and therefore inside `.xcdatamodeld` package, however the headers are all copied to the public headers directory when the library is built.

Compile, Build or Archive problems with Xcode 4 (and dependencies)

Is gcc C compiler written in C itself ? Or is it written in Assembly ? If the compiler is written in C, then what is the compiler used to compile the compiler code ?


Is gcc C compiler written in C itself?

Can someone please tell me how to create a static library from a .cpp and a .hpp file? Do I need to create the .o and the .a? I would also like to know how can I compile a static library in and use it in other .cpp code. I have `header.cpp`, `header.hpp .` I would like to create `header.a`. Test the header.a in `test.cpp`. I am using g++ for compiling.

How to create a static library with g++?

I would like to make groups of the text content of an `&lt;option /&gt;` tag. Say I have the following: `&lt;option&gt;8:00 (1 hour)&lt;/option&gt;`, the time pattern `8:00` can be modified, then the text in parenthesis `(1 hour)` can also be modified.

I was thinking of doing something like

&lt;!-- language: lang-html --&gt;

    &lt;option&gt;
      &lt;span&gt;8:00&lt;/span&gt;
      &lt;span&gt; (1 hour)&lt;/span&gt;
    &lt;/option&gt;

Is it bad to put `&lt;span /&gt;` tags inside `&lt;option /&gt;` tags, only for string manipulation not styling?

Is it bad to put &lt;span /&gt; tags inside &lt;option /&gt; tags, only for string manipulation not styling?

I know the `--verbose` or `-v` from several tools and I&#39;d like to implement this into some of my own scripts and tools.

I thought of placing:

    if verbose:
        print ...

through my source code, so that if a user passes the `-v` option, the variable `verbose` will be set to `True` and the text will be printed.

Is this the right approach or is there a more common way?

Addition: I am not asking for a way to implement the parsing of arguments. That I know how it is done. I am only interested specially in the verbose option.


How to implement the --verbose or -v option into a script?

Is it possible to change the option menu items programmatically? Can anyone provide me with an example please?

Also, I want to disable certain items, so that they don&#39;t listen to the clicks, is it possible?

android: changing option menu items programmatically

    // opt_options is optional
    function foo(a, b, opt_options) {
      // opt_c, opt_d, and opt_e are read from &#39;opt_options&#39;, only c and d have defaults
      var opt_c = &#39;default_for_c&#39;;
      var opt_d = &#39;default_for_d&#39;;
      var opt_e; // e has no default
    
      if (opt_options) {
        opt_c = opt_options.c || opt_c;
        opt_d = opt_options.d || opt_d;
        opt_e = opt_options.e;
      }
    }

The above seems awfully verbose. What&#39;s a better way to handle argument options with default parameters?

A javascript design pattern for options with default values?

If I have a `List[Option[A]]` in Scala, what is the idiomatic way to filter out the `None` values?

One way is to use the following:

    val someList: List[Option[String]] = List(Some(&quot;Hello&quot;), None, Some(&quot;Goodbye&quot;))
    someList.filter(_ != None)

Is there a more &quot;idiomatic&quot; way? This does seem pretty simple.


How to filter None&#39;s out of List[Option]?

I am having some difficulty compiling a C++ program that I&#39;ve written.

This program is very simple and, to the best of my knowledge, conforms to all the rules set forth in the C++ Standard.  I&#39;ve read over the entirety of ISO/IEC 14882:2003 twice to be sure.

The program is as follows:

![enter image description here][1]

Here is the output I received when trying to compile this program with Visual C++ 2010:
    
    c:\dev&gt;cl /nologo helloworld.png
    cl : Command line warning D9024 : unrecognized source file type &#39;helloworld.png&#39;, object file assumed
    helloworld.png : fatal error LNK1107: invalid or corrupt file: cannot read at 0x5172

Dismayed, I tried g++ 4.5.2, but it was equally unhelpful:

    c:\dev&gt;g++ helloworld.png
    helloworld.png: file not recognized: File format not recognized
    collect2: ld returned 1 exit status

I figured that Clang (version 3.0 trunk 127530) must work, since it is so highly praised for its standards conformance.  Unfortunately, it didn&#39;t even give me one of its pretty, highlighted error messages:

    c:\dev&gt;clang++ helloworld.png
    helloworld.png: file not recognized: File format not recognized
    collect2: ld returned 1 exit status
    clang++: error: linker (via gcc) command failed with exit code 1 (use -v to see invocation)

To be honest, I don&#39;t really know what any of these error message mean.

Many other C++ programs have source files with a _.cpp_ extension, so I thought perhaps I needed to rename my file.  I changed its name to _helloworld.cpp_, but that didn&#39;t help.  I think there is a very serious bug in Clang because when I tried using it to compile the renamed program, it flipped out, printed &quot;84 warnings and 20 errors generated.&quot; and made my computer beep a lot!

What have I done wrong here?  Have I missed some critical part of the C++ Standard?  Or are all three compilers really just so broken that they can&#39;t compile this simple program?  

  [1]: http://i.stack.imgur.com/JQXWL.png

Why is this program erroneously rejected by three C++ compilers?

I have a question concerning llvm, clang, and gcc on OS X. 

What is the difference between the llvm-gcc 4.2, llvm 2.0 and clang? I know that they all build on llvm but how are they different? 

Besides faster compiling, what is the advantage of llvm over gcc?

LLVM vs clang on OS X

I have a virtual Debian system which I use to develop.

Today I wanted to try llvm/clang.

After installing clang I can&#39;t compile my old c-projects (with gcc).
This is the error:

    ...
    /usr/bin/ld: cannot find crt1.o: No such file or directory
    /usr/bin/ld: cannot find crti.o: No such file or directory
    collect2: ld returned 1 exit status
    ...

I uninstalled clang and it still did not work.

Does anyone have any idea how I can fix this?

Compiling problems: cannot find crt1.o

### Alternate Titles
- List of Xcode build variables
- Print a list of Xcode Build Settings
- Clang Environment Variables
- Canonical list of Xcode Environment Variables

Is there a *Canonical list of Xcode Environment Variables* that can be used in *Build Rules* etc?

Content Type	Original Author	Original Content on Stackoverflow
Question	eonil	View Question on Stackoverflow
Solution 1 - C	Matt Joiner	View Answer on Stackoverflow
Solution 2 - C	Paul R	View Answer on Stackoverflow
Solution 3 - C	user142019	View Answer on Stackoverflow

What's the difference between GNU99 and C99 (Clang)?

C Problem Overview

C Solutions

Solution 1 - C

Differences between various standard modes

More links

Solution 2 - C

Solution 3 - C

How can I run an EXE program from a Windows Service using C#?

ADO.NET DbContext Generator vs. ADO.NET Poco Entity Generator (ObjectContext)

Attributions